Perfluoroalkyl-crosslinked fluoropolymer with perfluoroether pendant groups

ABSTRACT

This invention pertains to a novel perfluoroalkyl-crosslinked fluoropolymer with perfluoroether pendant groups. The perfluoroalkyl-crosslinked fluoropolymer hereof is particularly well-suited for use in chemically and thermally aggressive environments, in part by virtue of the highly stable perfluoroalkyl crosslink. The perfluroalkyl-crosslinked fluoropolymer hereof can be prepared by crosslinking in situ a crosslinkable precursor in the form of a shaped article. A crosslinkable precursor is a fluoropolymer having a dichloroamino-functionalized functionalized perfluoroether pendant group.

CLAIM OF PRIORITY

The present invention claims priority to U.S. Provisional PatentApplications 61/706,858, entitled “Perfluoroalkyl-CrosslinkedFluoropolymer With Perfluoroether Pendant Groups,” filed on Sep. 28,2012.

FIELD OF THE INVENTION

This invention pertains to a novel perfluoroalkyl-crosslinkedfluoropolymer with perfluoroether pendant groups. Theperfluoroalkyl-crosslinked fluoropolymer hereof is particularlywell-suited for use in chemically and thermally aggressive environments,in part by virtue of the highly stable perfluoroalkyl crosslink. Theperfluroalkyl-crosslinked fluoropolymer hereof can be prepared bycrosslinking in situ a crosslinkable precursor in the form of a shapedarticle. A crosslinkable precursor is a fluoropolymer having adichloroamino-functionalized functionalized perfluoroether pendantgroup.

BACKGROUND

Hynes et al., inorganic Chemistry, 5 (3) 488-489 (March 1966), disclosecompositions of the formula R_(f)CF₂NCl₂ wherein R_(f) is CF₃ or C₂F₅.They also disclose CClF₂CF₂NCl₂, and NCl₂CF₂CF₂CF₂NCl₂. Furtherdisclosed is a process for synthesizing those species by reacting at−78° C. the condensed vapors of, respectively, C₂F₅CN, C₃F₇CN, CCl—F₂CN,and CF₂(CN)₂, with Cl—F, followed by warming to 0° C. Further disclosedis the pyrolytic transformation at ca. 200° C. of the fluorinatedchloroamines to azo compounds represented, inter alia, by the structureR_(f)CF₂N═NCF₂R_(f) where R_(f) is CF₃, C₂F₅, or CCl—F₂, as well as acyclic structure when the starting material was NCl₂CF₂CF₂CF₂NCl₂. Thesubsequent thermolysis of azo R_(f)CF₂N═NCF₂R_(f) has been reported tofollow multiple reaction paths (Scherer, Jr. et al., InternationalJournal of Kinetics, 26, 73(1994)).

Logothetis, U.S. Pat. No. 5,447,993 discloses nitrile containingfluoroelastomers that are copolymers of tetrafluoroethylene, aperfluoro(alkyl vinyl ether) and a nitrile containing cure site monomer.Particularly preferred is the cure site monomer represented by thestructureCF₂═CFOCF₂CF(CF₃)OCF₂CF₂CNAlso disclosed in Logothetis is a process for crosslinking thenitrile-containing fluoroelastomer comprising using a tin catalystcapable of catalyzing the crosslinking, a peroxide, and a diene ortriene coagent, the process comprising heating first to 150 to 220° C.followed by further heating to 250 to 310° C. The second heating is saidto produce a cured sample that is thermally stable.

SUMMARY OF THE INVENTION

In one aspect the invention provides a dichloroamino-functionalizedpolymer having a backbone chain comprising fluoroalkylene repeat unitsoptionally substituted by ether oxygen, and a molar concentration of 0.5to 50 mol-% of repeat units represented by Structure I

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; R₃is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; withthe proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saiddichloroamino-functionalized polymer has more than two vinyl hydrogensattached thereto; and, wherein said dichloroamino-functionalized polymerhas no crystalline melting point above 180° C. that is associated with alatent heat of melting greater than 1 J/g.

In another aspect, the invention provides a Cl—F addition processcomprising combining, at a temperature in the range of 20 to 150° C.,Cl—F with a cyano-functionalized polymer comprising fluoroalkylenerepeat units optionally substituted by ether oxygen, and a molarconcentration of 0.5 to 50 mol-% of repeat units represented byStructure II

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; andR₃ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;with the proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saidcyano-functionalized polymer has more than two vinyl hydrogens attachedthereto.

In another aspect the invention provides an azo-crosslinked polymerrepresented by Structure III

wherein each of Π_(α) and Π_(β) is a polymeric radical having a backbonechain comprising fluoroalkylene repeat units optionally substituted byether oxygen, and azo-crosslinked repeat units at a molar concentrationin the range of a molar concentration of 0.5 to 50 mol-%; where x₁ andx₂ each independently is an integer in the range of 0 to 3; y₁ and y₂each independently is an integer in the range of 0 to 6, and z₁ and z₂each independently is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;R₁′=(CF₂)_(a′)CFR₂′ where a′ is an integer in the range of 0 to 6, andR₂′ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;and, R₃ and R₃′ are each independently F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen; with the proviso that y₁ and z₁cannot both be zero; with the further proviso that y₂ and z₂ cannot bothbe zero; with the further proviso that no repeat unit in the backbonechain of said Π_(α) and Π_(β) polymeric radicals has more than two vinylhydrogens attached thereto; and, with the further proviso that Π_(α) andΠ_(β) can be the same or different.

In another aspect, the invention provides an azo formation processcomprising combining a first dichloroamino-functionalized polymer havinga first backbone chain and a second dichloroamino-functionalized polymerhaving a second backbone chain to form a reaction mixture, andsubjecting said thus formed reaction mixture to exposure to ultra-violetirradiation, at least a portion of which lies in the wavelength rangefrom 200 to 425 nm for a period of time sufficient to convert at least aportion of said first and second polymers into a crosslinked product,each said first and second backbone chains comprising fluoroalkylenerepeat units optionally substituted by ether oxygen, and a molarconcentration in the range of a molar concentration of 0.5 to 50 mol-%of dichloroamino-functionalized repeat units represented by Structure I

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; R₃is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; withthe proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saiddichloroamino-functionalized polymer has more than two vinyl hydrogensattached thereto; and, wherein said dichloroamino-functionalized polymerhas no crystalline melting point above 180° C. that is associated with alatent heat of melting greater than 1 J/g; and, wherein said firstpolymer and said second polymer can be the same or different.

In still another aspect, the invention provides a crosslinkstabilization process comprising subjecting an azo-crosslinked polymerto a temperature in the range of 200 to 350° C. for a period of timesufficient to convert at least a portion of said azo crosslinked polymerto a perfluoroalkyl-crosslinked polymeric structure; saidazo-crosslinked polymer represented by Structure III

wherein each of Π_(α) and Π_(β) is a polymeric radical having a backbonechain comprising fluoroalkylene repeat units optionally substituted byether oxygen, and azo-crosslinked repeat units at a molar concentrationin the range of a molar concentration of 0.5 to 50 mol-%; where x₁ andx₂ each independently is an integer in the range of 0 to 3; y₁ and y₂each independently is an integer in the range of 0 to 6, and z₁ and z₂each independently is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen;R₁′=(CF₂)_(a′)CFR₂′ where a′ is an integer in the range of 0 to 6, andR₂′ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;and, R₃ and R₃′ are each independently F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen; with the proviso that y₁ and z₁cannot both be zero; with the further proviso that y₂ and z₂ cannot bothbe zero; with the further proviso that no repeat unit in the backbonechain of said Π_(α) and Π_(β) polymeric radicals has more than two vinylhydrogens attached thereto; and, with the further proviso that Π_(α) andΠ_(β) can be the same or different.

In another aspect, the invention provides a perfluoroalkyl-crosslinkedpolymer comprising a fluorocarbon crosslinked polymer represented byStructure IV

wherein each of Π_(α) and Π_(β) is a polymeric radical having a backbonechain comprising fluoroalkylene repeat units optionally substituted byether oxygen, and perfluoroalkyl-crosslinked repeat units at a molarconcentration in the range of a molar concentration of 0.5 to 50 mol-%;where x₁ and x₂ each independently is an integer in the range of 0 to 3;y₁ and y₂ each independently is an integer in the range of 0 to 6, andz₁ and z₂ each independently is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen;R₁′=(CF₂)_(a′)CFR₂′ where a′ is an integer in the range of 0 to 6, andR₂′ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;and, R₃ and R₃′ are each independently F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen; with the proviso that y₁ and z₁cannot both be zero; with the further proviso that y₂ and z₂ cannot bothbe zero; with the further proviso that no repeat unit in the backbonechain of said Π_(α) and Π_(β) polymeric radicals has more than two vinylhydrogens attached thereto; and, with the further proviso that Π_(α) andΠ_(β) can be the same or different.

In another aspect, the invention provides for A process comprisingforming a reaction mixture by adding Cl—F, at a temperature in the rangeof room temperature to 100° C., to an evacuated vessel containing acyano-functionalized polymer comprising a backbone chain comprisingrepeat units of tetrafluoroethylene, perfluoromethylvinyl ether, and amolar concentration in the range of 0.5 to 5 mol-% of repeat unitsrepresented by Structure VI

wherein said cyano-functionalized polymer has no crystalline meltingpoint above 180° C. that is associated with a latent heat of meltinggreater than 1 J/g; subjecting said reaction mixture to heating to atemperature in the range of 250 to 300° C.; removing residual Cl—Ffollowing the step of heating in the range 250 to 300° C., followed byfurther heating the polymer to a temperature in the range of >300 to350° C. in an inert atmosphere.

In still another aspect, the present invention provides an imageablearticle comprising a substrate having a surface, and an imageable filmdisposed upon said surface, said imageable film comprising adichloroamino-functionalized polymer comprising fluoroalkylene repeatunits optionally substituted by ether oxygen, and a molar concentrationin the range of a molar concentration of 0.5 to 50 mol-% of repeat unitsrepresented by Structure I

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; R₃is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; withthe proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saiddichloroamino-functionalized polymer has more than two vinyl hydrogensattached thereto; and, wherein said dichloroamino-functionalized polymerhas no crystalline melting point above 180° C. that is associated with alatent heat of melting greater than 1 J/g.

In a further aspect the invention provides a method comprising imagewiseexposing an imageable article to ultra-violet light at least a portionof which lies in the wavelength range from 200 to 425 nanometers; and,subjecting the thus imagewise exposed imaged article to imagedevelopment, thereby producing an imaged article; wherein said imageablearticle comprises a substrate having a surface, and an imageable filmdisposed upon said substrate, said imageable film comprising adichloroamino-functionalized polymer comprising fluoroalkylene repeatunits optionally substituted by ether oxygen, and a molar concentrationof 0.5 to 50 mol-% of repeat units represented by Structure I

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; R₃is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; withthe proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saiddichloroamino-functionalized polymer has more than two vinyl hydrogensattached thereto; and, wherein said dichloroamino-functionalized polymerhas no crystalline melting point above 180° C. that is associated with alatent heat of melting greater than 1 J/g.

In another aspect, the present invention provides an imaged articlecomprising a substrate having a surface, and a crosslinked coatingimagewise disposed upon said surface, said crosslinked coatingcomprising an azo-crosslinked polymer represented by Structure III

wherein each of Π_(α) and Π_(β) is a polymeric radical having a backbonechain comprising fluoroalkylene repeat units optionally substituted byether oxygen, and azo-crosslinked repeat units at a molar concentrationin the range of a molar concentration of 0.5 to 50 mol-%; where x₁ andx₂ each independently is an integer in the range of 0 to 3; y₁ and y₂each independently is an integer in the range of 0 to 6, and z₁ and z₂each independently is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;R₁′=(CF₂)_(a′)CFR₂′ where a′ is an integer in the range of 0 to 6, andR₂′ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;and, R₃ and R₃′ are each independently F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen; with the proviso that y₁ and z₁cannot both be zero; with the further proviso that y₂ and z₂ cannot bothbe zero; with the further proviso that no repeat unit in the backbonechain of said Π_(α) and Π_(β) polymeric radicals has more than two vinylhydrogens attached thereto; and, with the further proviso that Π_(α) andΠ_(β) can be the same or different.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an optical photomicrograph showing ˜20 and 50μ wide groovesdeveloped after exposing the P5-CF2NCl2 film in Example 16 to UV lightthough a photomask.

FIG. 2a is an AFM (Atomic Force Microscopy) micrograph of 10 micrometerlines spaced at 20 micrometers developed after exposing the P5CF₂NCl₂film in Example 16 to UV light though a photomask.

FIG. 2b shows an AFM sectional analysis of the pattern in FIG. 2 a.

FIG. 3a is an optical photograph of the clear and colorless startingo-ring of P3-CF₂CF₂—P3-25a of Example 25 before heating in water at 325°C. FIG. 3b shows the o-ring of FIG. 3a after heating in water at 325° C.

FIG. 4a is an optical photograph of the clear and colorless startingo-ring of P3-CF₂CF₂—P3-25b of Example 25 before heating in water at 325°C. FIG. 4b shows the o-ring of FIG. 4a after heating in water at 325° C.

DETAILED DESCRIPTION

When a range of values is provided herein, it is intended to encompassthe end-points of the range unless specifically stated otherwise.Numerical values used herein have the precision of the number ofsignificant figures provided, following the standard protocol inchemistry for significant figures as outlined in ASTM E29-08 Section 6.For example, the number 40 encompasses a range from 35.0 to 44.9,whereas the number 40.0 encompasses a range from 39.50 to 40.49.

The term “room temperature” shall be understood to mean that no externalheating or cooling has been applied to the specimen in question. Ingeneral, room temperature for the purposes of this invention lies in therange of 20-35° C., most typically 23-30° C.

The terms “melting point,” “melting endotherm,” and “latent heat ofmelting” are employed herein in a manner consistent with common usage inthe art of polymer science. Terminology is referenced to the resultsobtained by employing the thermal analytical technique of differentialscanning calorimetry (DSC). Unlike crystalline small molecules,crystalline organic polymers exhibit melting over a range oftemperatures, and the melting transition is characterized in a number ofways. The output of DSC analysis of an organic polymer describes acontinuous curve that rises continuously from the base line, reaches apeak, and then falls gradually and continuously back to the baseline.That curve is referred to as a melting endotherm. For the purposes ofthe present invention, the temperature at which the melting endothermreaches its peak is referred to herein as the “melting point” of thepolymer. The integral of the melting endotherm corresponds to the latentheat of melting of the crystalline polymer. Thus each melting point isassociated with a melting endotherm, and a latent heat of melting isassociated with each melting point.

The polymers suitable for the processes disclosed herein are amorphouspolymers, exhibiting no substantial amount of crystallinity. Moreparticularly, a suitable polymer is one which exhibits no melting pointat a temperature of >180° C. with an associated latent heat of meltinggreater than 1 J/g. Preferably, a suitable polymer is one which exhibitsno melting point at a temperature of >150° C. with an associated latentheat of melting greater than 1 J/g.

The term “solvent soluble” is employed herein to describe someembodiments of the polymers described herein. By “solvent soluble” ismeant that the indicated polymer is soluble in an organic solvent thatis a liquid at room temperature. Particularly well-suited solvents areperfluorinated solvents. Suitable perfluorinated solvents include butare not limited to perfluoro-N-methylmorpholine, available commerciallyfrom the 3M Company as PF-5052, and Fluorinert® FC-40, also availablefrom the 3M Company.

Disclosed herein is a novel, non-crosslinked fluoropolymer, comprising aperfluoroether pendant group comprising a —CF₂NCl₂ functional group, andthe preparation thereof from a known polycyanofluorovinyl ether bytreatment with Cl—F; the crosslinking thereof by exposure toultra-violet (UV) to form a novel azo crosslinked polymer; and, a novel,highly thermally stable, crosslinked polymer comprisingperfluoroalkylene crosslinks, and a plurality of methods for thepreparation thereof. Further disclosed is the use of these polymers forpreparing highly stable molded articles. Also disclosed is the imagewiseexposure of these polymers to UV, and the preparation thereby of imagedarticles.

Terms such as uncrosslinked and crosslinked shall be understood to referto a preponderance of functional groups in a given polymer, but notnecessarily, and not usually, to all. Thus, it shall be understood thatwhen a polymer is described as uncrosslinked or “not substantiallycrosslinked” it means that a preponderance of the crosslinkable groupsremain uncrosslinked, and that the properties of the polymer socharacterized are characteristic of uncrosslinked polymers, such as bysolubility, thermo-formability, dimensional stability (or, moreprecisely, instability), melt flowability, and such other propertiessuch as are known in the art to pertain to uncrosslinked polymers.

It shall further be understood that when a polymer is described ascrosslinked or “substantially crosslinked” it means that a preponderanceof the crosslinkable groups originally available in the uncrosslinkedpolymer have undergone crosslinking and that the properties of thepolymer so characterized are characteristic of crosslinked polymers,exhibiting differences vis a vis the corresponding uncrosslinkedpolymer, of reduced solubility, reduced thermo-formability, increaseddimensional stability, and decreased melt flowability, as well asexhibiting such other properties as are known in the art to pertain tocrosslinked polymers.

In several embodiments, chemical reaction is effected in situ in apolymeric shaped article. The total reaction time will depend directlyupon the thickness of the shaped article, and inversely upon the surfaceto volume ratio thereof. Desirably, sufficient time is allowed forreactants to diffuse into the polymeric shaped article, and forby-products to diffuse out. The thicker the shaped article, the longertime for diffusion, other things being equal. Similar considerationshold for heating profiles. Excessively rapid heating can lead to foamingand blistering because reaction by-products cannot escape. The thickerthe polymeric shaped article, the more gradual heating needs to be; so,heating time varies directly with thickness.

As a result, the heating time required in a given process step has beenobserved to vary very considerably. When the article being heated toeffect crosslinking is a film that might be 25-100 micrometers thick,crosslinking may be effected to completion in the time range of 10seconds to 10 minutes. On the other hand, if the article beingcrosslinked is on the order of 1000-5000 micrometers in thickness, aslong as 30 hours might be required to achieve uniform and completecrosslinking.

It is common practice in the polymer art to refer to repeat units inpolymer backbones according to the monomeric species from which therepeat unit has been formed. That practice will be employed herein.Thus, for example, the repeat unit in poly(tetrafluoro ethylene) isreferred to as a tetrafluoroethylene (TFE) repeat unit, even though, infact it is the diradical —CF₂—CF₂— that is incorporated into thebackbone upon polymerization of the TFE.

In one aspect the invention provides a dichloroamino-functionalizedpolymer having a backbone chain comprising fluoroalkylene repeat unitsoptionally substituted by ether oxygen, and a molar concentration of 0.5to 50 mol-% of repeat units represented by Structure I

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; R₃is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; withthe proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saiddichloroamino-functionalized polymer has more than two vinyl hydrogensattached thereto; and, wherein said dichloroamino-functionalized polymerhas no crystalline melting point above 180° C. that is associated with alatent heat of melting greater than 1 J/g.

In one embodiment of the dichloroamino-functionalized polymer, x=1, y=1,z=1, a=1, R₂=CF₃; and R₃=F.

In one embodiment of the dichloroamino-functionalized polymer, the molarconcentration of repeat units represented by Structure I is in the rangeof mol-%. In a further embodiment, the concentration of repeat unitsrepresented by Structure I is in the range of 0.5 to 5 mol-%.

In one embodiment, the dichloroamino-functionalized polymer furthercomprises repeat units of perfluoroalkyl vinyl ether (PAVE). In afurther embodiment, the PAVE is perfluoromethyl vinyl ether (PMVE),perfluoroethyl vinyl ether (PEVE), perfluoropropyl vinyl ether (PPVE),perfluorobutyl vinyl ether (PBVE), or a combination of two or morethereof.

In one embodiment of the dichloroamino-functionalized polymer at least aportion of the fluoroalkylene repeat units are branched fluoroalkylenerepeat units.

Suitable fluoroalkylene repeat units include but are not limited tothose derived from tetrafluoroethylene (TFE), hexafluoropropylene (HFP),vinylidene fluoride (VF₂), perfluorodimethyldioxole (PDD), or acombination of two or more thereof. Particularly suitable arecombinations of fluoroalkylene repeat units such as HFP with VF₂, andTFE with PDD.

In one embodiment, the dichloroamino-functionalized polymer has nocrystalline melting point above 150° C. that is associated with a latentheat of melting greater than 1 J/g.

In one embodiment the dichloroamino-functionalized polymer ischaracterized by a backbone chain comprising repeat units oftetratfluoroethylene, perfluoromethylvinyl ether, and a molarconcentration in the range of 0.5 to 5 mol-% of repeat units representedby Structure V

wherein said dichloroamino-functionalized polymer has no crystallinemelting point above 150° C. that is associated with a latent heat ofmelting greater than 1 J/g.

In another aspect, the invention provides a Cl—F addition processcomprising combining, at a temperature in the range of room temperatureto 100° C., Cl—F with a cyano-functionalized polymer comprisingfluoroalkylene repeat units optionally substituted by ether oxygen, anda molar concentration of 0.5 to 50 mol-% of repeat units represented byStructure II

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; andR₃ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;with the proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saiddichloroamino-functionalized polymer has more than two vinyl hydrogensattached thereto.

In one embodiment of the Cl—F addition process, in thecyano-functionalized polymer, x=1, y=1, z=1, a=1, R₂=CF₃; and R₃=F. Thisparticular repeat unit is derived from a monomer that shall be referredto herein as 8-CNVE.

In one embodiment of the Cl—F addition process, in thecyano-functionalized polymer, the molar concentration of repeat unitsrepresented by Structure II is in the range of 0.5 to 50 mol-%. In afurther embodiment of the Cl—F addition process, in thecyano-functionalized polymer, the molar concentration of repeat unitsrepresented by Structure II is in the range of 0.5 to 5 mol-%.

In one embodiment, the polymer represented by Structure II is solventsoluble. In an alternative embodiment, the polymer represented byStructure II is melt processible. In a further embodiment, the polymerrepresented by Structure II is both solvent soluble and meltprocessible. A melt processible polymer is particularly well-suited forthe formation of shaped articles by extrusion or molding. However, to beuseful therein, the crosslinking rate needs to be slow relative to thelength of time needed to form parts. For example, it is unlikely that auniform, properly shaped o-ring could be molded if starting with apolymer that crosslinks faster at mold temperature than adichloroamino-functionalized polymer of Structure I can melt flow andfill the mold. There are many variables to be considered including themold temperature needed to achieve adequate melt flow which will in turnbe impacted by polymer structure and molecular weight, the size andcomplexity of the parts to be molded, the concentration of —NCl₂ groupsin the polymer and the inherent reactivity of those particular —NCl₂groups at mold temperature. The specific conditions providing optimumyield, purity, properties and so forth for any particular polymer andpart can be determined empirically according to the methods set outherein, such as by a design of experiment approach.

In the Cl—F addition process hereof, the reaction is conducted in avessel with a pressure of Cl—F ranging from −6 to 200 psig. In oneembodiment, the Cl—F pressure is in the range of 0 to 100 psig. In afurther embodiment, the Cl—F pressure is in the range of 5 to 50 psig.

In one embodiment, the Cl—F addition process comprises combining, at atemperature in the range of 60 to 80° C., Cl—F at a pressure of 5 to 25psig with a cyano-functionalized polymer having a backbone chaincomprising repeat units of tetrafluoroethylene, perfluoromethylvinylether, and a molar concentration in the range of 0.5 to 5 mol-% ofrepeat units represented by Structure VI:

wherein said cyano-functionalized polymer has no crystalline meltingpoint above 150° C. that is associated with a latent heat of meltinggreater than 1 J/g.

Example 14 shows how, in one particular embodiment, a small change inprocessing conditions results in the difference between being able toprocess (six minutes for a film at 190° C.) and not being able toprocess (6 minutes at 200° C.) a given polymer.

Suitable cyano-functionalized polymers of which many embodiments aresolvent soluble, melt processible, or both, include but are not limitedto:

-   -   TFE/PAVE/8-CNVE copolymers wherein the PAVE repeat unit is PMVE,        PEVE, PPVE, PBVE, or a combination of two or more thereof,        wherein the repeat unit derived from the PAVE is present at a        concentration in the range of 18-49 mol %.    -   PDD/TFE/8-CNVE and PDD/8-CNVE copolymers wherein the PDD repeat        unit is present in the backbone at a concentration in the range        of 30 to 99 mol-%.    -   HFP/VF₂/8-CNVE copolymers wherein the HFP repeat unit is present        in the backbone at a concentration in the range of 15 to 50        mol-%.    -   HFP/TFE/8-CNVE copolymers wherein the HFP repeat unit is present        in the backbone at a concentration in the range of 25 to 35        mol-%.

Suitable cyano-functionalized polymers can be prepared according tomethods of the art as taught in U.S. Pat. No. 7,989,566 and U.S. Pat.No. 5,789,489, and as described in the specific embodiments describedinfra.

The dichloroamino-functionalized polymer is readily formed into shapedarticles, as well as coatings. In one embodiment of a shaped article, asolution of the dichloroamino-functionalized polymer is applied to thesurface of a substrate, and the solvent volatilized, to form aphotoimageable coating thereupon.

In an alternative embodiment, the dichloroamino-functionalized polymerhere is melt formed into a shape by injection or compression molding, byextrusion, or such other means as are known in the art for the formingof shaped articles from thermoplastic polymers. In a further embodiment,the thus formed shaped article is subject to cross-linking as describedin detail infra.

In another aspect the invention provides an azo-crosslinked polymerrepresented by Structure III

wherein each of Π_(α) and ø_(β) is a polymeric radical having a backbonechain comprising fluoroalkylene repeat units optionally substituted byether oxygen, and azo-crosslinked repeat units at a molar concentrationin the range of a molar concentration of 0.5 to 50 mol-%; where x₁ andx₂ each independently is an integer in the range of 0 to 3; y₁ and y₂each independently is an integer in the range of 0 to 6, and z₁ and z₂each independently is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;R₁′=(CF₂)_(a′)CFR₂′ where a′ is an integer in the range of 0 to 6, andR₂′ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;and, R₃ and R₃′ are each independently F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen; with the proviso that y₁ and z₁cannot both be zero; with the further proviso that y₂ and z₂ cannot bothbe zero; with the further proviso that no repeat unit in the backbonechain of said Π_(α) and Π_(β) polymeric radicals has more than two vinylhydrogens attached thereto; and, with the further proviso that Π_(α) andΠ_(β) can be the same or different.

In one embodiment of the azo-crosslinked polymer, Π_(α) and Π_(β) arethe same.

In an alternative embodiment of the azo-crosslinked polymer, Π_(α) andΠ_(β) are different.

In one embodiment of the azo-crosslinked polymer, Π_(α) and Π_(β) arethe same, x₁, x₂, y₁, y₂, z₁, z₂, and a=1; R₂ and R₂′=CF₃; and R₃ andR₃′=F.

In determining herein the molar concentration of crosslinked units, eachcrosslinked unit is counted as two units in the crosslinked structure inorder to keep the molar concentrations consistent from uncrosslinkedstructures to the corresponding crosslinked structure.

In one embodiment of the azo-crosslinked polymer the molar concentrationof azo-crosslinked repeat units as represented in Structure III is inthe range of 0.5 to 50 mol-%. In a further embodiment of theazo-crosslinked polymer the molar concentration of azo-crosslinkedrepeat units as represented in Structure III is in the range of 0.5 to 5mol-%.

In one embodiment of the azo-crosslinked polymer at least one of Π_(α)and Π_(β) further comprises PAVE repeat units. In a further embodiment,PAVE is PMVE, PEVE, PPVE, PBVE, or a combination of two or more thereof.In a still further embodiment, both Π_(α) and Π_(β) further comprisePAVE repeat units.

In one embodiment of the azo-crosslinked polymer at least a portion ofthe fluoroalkylene repeat units are branched fluoroalkylene repeatunits.

Suitable fluoroalkylene repeat units include but are not limited tothose derived from tetrafluoroethylene (TFE), hexafluoropropylene (HFP),vinylidene fluoride (VF₂), and perfluorodimethyldioxole (PDD).Particularly suitable are combinations of fluoroalkylene repeat unitssuch as such as HFP with VF₂, and TFE with PDD.

The azo-crosslinked polymer disclosed herein includes embodiments inwhich two or more azo-crosslinked polymers represented by Structure IIIare blended or otherwise mixed together before crosslinking.

In another aspect, the invention provides an azo formation processcomprising combining a first dichloroamino-functionalized polymer havinga first backbone chain and a second dichloroamino-functionalized polymerhaving a second backbone chain to form a reaction mixture, andsubjecting said thus formed reaction mixture to exposure to ultra-violetirradiation, at least a portion of which lies in the wavelength rangefrom 200 to 425 nm for a period of time sufficient to convert at least aportion of said first and second dichloroamino-functionalized polymersinto a crosslinked product, each said first and second backbone chainsof said first and second dichloroamino-functionalized polymerscomprising fluoroalkylene repeat units optionally substituted by etheroxygen, and a molar concentration of 0.5 to 50 mol-% of repeat unitsrepresented by Structure I

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; R₃is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; withthe proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saiddichloroamino-functionalized polymer has more than two vinyl hydrogensattached thereto; and, wherein said dichloroamino-functionalized polymerhas no crystalline melting point above 180° C. that is associated with alatent heat of melting greater than 1 J/g; and, wherein said firstpolymer and said second polymer can be the same or different.

In one embodiment of the azo-formation process, the firstdichloroamino-functionalized polymer and the seconddichloroamino-functionalized polymer are the same.

In an alternative embodiment of the azo-formation process, the first andthe second dichloroamino-functionalized polymer are different.

Embodiments of the process include those in which three or moredifferent polymers represented by Structure I are combined and reactedtogether to form the azo-crosslinked polymer.

In one embodiment of the azo-formation process, the UV irradiation lieswithin the wavelength range of 250-370 nm.

In one embodiment of the azo-formation process, said first and secondpolymers each independently have no crystalline melting point above 150°C. that is associated with a latent heat of melting greater than 1 J/g.

In one embodiment of the azo-formation process, thedichloroamino-functionalized polymer is characterized by a molarconcentration of repeat units represented by Structure I in the range of0.5 to 50 mol-%.

In one embodiment of the azo-formation process, thedichloroamino-functionalized polymer is that embodiment wherein x=1,y=1, z=1, a=1, R₂=CF₃; and R₃=F.

In one embodiment of the azo-formation process, thedichloroamino-functionalized polymer further comprises repeat units ofPAVE. In a further embodiment, the PAVE is PMVE, PEVE, PPVE, PBVE, or acombination of two or more thereof.

In one embodiment of the azo-formation process, thedichloroamino-functionalized polymer comprises branched fluoroalkylenerepeat units. Suitable fluoroalkylene repeat units include but are notlimited to those derived from TFE, HFP, VF₂, and PDD. Particularlysuitable are combinations of fluoroalkylene repeat units such as such asHFP with VF₂, and TFE with PDD.

Preferably the dichloroamino-functionalized polymer suitable for use inthe azo-formation process is solvent soluble, melt processible, or both.For the purpose of brevity, in the list that follows, the relevantembodiments of the monomer unit represented by Structure I shall bedesignated as 8-CF₂NCl₂VE.

Suitable dichloroamino-functionalized polymers of which many embodimentsare solvent soluble, melt processible, or both, include but are notlimited to:

-   -   TFE/PAVE/8-CF₂NCl₂VE copolymers wherein the PAVE repeat unit is        PMVE, PEVE, PPVE, PBVE, or a combination of two or more thereof,        wherein the repeat unit derived from the PAVE is present at a        concentration in the range of 18-49 mol %.    -   PDD/TFE/8-CF₂NCl₂VE and PDD/8-CF₂NCl₂VE copolymers wherein the        PDD repeat unit is present in the backbone at a concentration in        the range of 30 to 99 mol-%.    -   HFP/VF₂/8-CF₂NCl₂VE copolymers wherein the HFP repeat unit is        present in the backbone at a concentration in the range of 15 to        50 mol-%.    -   HFP/TFE/8-CF₂NCl₂VE copolymers wherein the HFP repeat unit is        present in the backbone at a concentration in the range of 25 to        35 mol-%.

In one embodiment of the azo formation process, the UV exposure isperformed in an inert atmosphere. Suitable inert atmospheres include butare not limited to nitrogen, argon, helium or a mixture thereof.

In one embodiment, the azo formation process comprises subjecting toultra-violet irradiation in the wave-length range from 250 to 370 nm, adichloroamino-functionalized polymer having a backbone chain for aperiod of time sufficient to convert at least a portion of saiddichloroamino-functionalized polymer into a crosslinked product; saidbackbone chain comprising repeat units of tetrafluoroethylene,perfluoromethylvinyl ether, and a molar concentration in the range of0.5 to 5 mol-% of dichloroamino-functionalized repeat units representedby Structure V

wherein said dichloroamino-functionalized polymer has no crystallinemelting point above 150° C. that is associated with a latent heat ofmelting greater than 1 J/g.

In still another aspect, the invention provides a crosslinkstabilization process comprising subjecting an azo crosslinked polymerto a temperature in the range of 250 to 350° C. for a period of timesufficient to convert at least a portion of said azo crosslinked polymerto a perfluoroalkyl-crosslinked polymeric structure; saidazo-crosslinked polymer represented by Structure III

wherein each of ø_(α) and Π_(β) is a polymeric radical having a backbonechain comprising fluoroalkylene repeat units optionally substituted byether oxygen, and azo-crosslinked repeat units at a molar concentrationin the range of a molar concentration of 0.5 to 50 mol-%; where x₁ andx₂ each independently is an integer in the range of 0 to 3; y₁ and y₂each independently is an integer in the range of 0 to 6, and z₁ and z₂each independently is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen;R₁′=(CF₂)_(a′)CFR₂′ where a′ is an integer in the range of 0 to 6, andR₂′ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;and, R₃ and R₃′ are each independently F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen; with the proviso that y₁ and z₁cannot both be zero; with the further proviso that y₂ and z₂ cannot bothbe zero; with the further proviso that no repeat unit in the backbonechain of said Π_(α) and Π_(β) polymeric radicals has more than two vinylhydrogens attached thereto; and, with the further proviso that Π_(α) andΠ_(β) can be the same or different.

In one embodiment, the crosslink stabilization process is conducted inan inert atmosphere. Suitable inert atmospheres include nitrogen, argon,helium or a mixture thereof.

It has been found that the conversion of the azo crosslink to theperfluoroalkenyl crosslink (—CF₂CF₂—) first becomes apparent in ATRspectra around 200° C. Conversion of the azo-crosslinked polymer to the—CF₂CF₂— crosslinked polymer is preferably effected in the temperaturerange of 250 to 350° C., most preferably in the temperature range of 300to 350° C. Less than complete conversion of the azo to theperfluoroalkenyl —CF₂CF₂— crosslink results in a crosslinked polymerthat can be both thermally and hydrolytically unstable. The instabilitycan be dimensional, hydrolytic, or both. Theperfluoroalkenyl-crosslinked polymeric structure produced in thecrosslink stabilization process remains relatively inert to thermalexposure between room temperature and about 380 to 390° C. and tochemical exposure such as water to at least 325° C.

While the operability of the crosslink stabilization process is notlimited by any particular chemical mechanism, there is strong chemicalevidence, as demonstrated in the specific embodiments provided infra,that the crosslink stabilization process causes the conversion of theazo-crosslinked polymer to the correspondingperfluoroalkenyl-crosslinked polymer represented by Structure IV,described infra, by driving off the nitrogens.

In one embodiment, the crosslink stabilization process comprisessubjecting azo-crosslinked polymer to a temperature in the range of 300to 350° C. for a period of time sufficient to convert at least a portionof said azo crosslinked polymer to a perfluoroalkyl-crosslinkedpolymeric structure; said azo-crosslinked polymer represented byStructure VII:

wherein π is a polymeric radical having a backbone chain comprisingrepeat units of tetrafluoroethylene, perfluoromethyvinyl ether, andazo-crosslinked repeat units at a molar concentration of 0.5 to 5 mol-%.

In another aspect, the invention provides a perfluoroalkenyl-crosslinkedpolymer represented by Structure IV

wherein each of Π_(α) and Π_(β) is a polymeric radical having a backbonechain comprising fluoroalkylene repeat units optionally substituted byether oxygen, and perfluoroalkenyl-crosslinked repeat units at a molarconcentration in the range of a molar concentration of 0.5 to 50 mol-%;where x₁ and x₂ each independently is an integer in the range of 0 to 3;y₁ and y₂ each independently is an integer in the range of 0 to 6, andz₁ and z₂ each independently is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;R₁′=(CF₂)_(a′)CFR₂′ where a′ is an integer in the range of 0 to 6, andR₂′ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;and, R₃ and R₃′ are each independently F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen; with the proviso that y₁ and z₁cannot both be zero; with the further proviso that y₂ and z₂ cannot bothbe zero; with the further proviso that no repeat unit in the backbonechain of said Π_(α) and Π_(β) polymeric radicals as more than two vinylhydrogens attached thereto; and, with the further proviso that Π_(α) andΠ_(β) can be the same or different.

In one embodiment of the perfluoroalkenyl-crosslinked polymer, Π_(α) andΠ_(β) are the same.

In an alternative embodiment of the perfluoroalkenyl-crosslinkedpolymer, Π_(α) and Π_(β) are different.

The perfluoroalkenyl-crosslinked polymer includes embodiments in whichtwo or more perfluoroalkenyl-crosslinked polymers represented byStructure III are combined in a blend.

In one embodiment of the perfluoroalkenyl-crosslinked polymer, Π_(α) andΠ_(β) are the same, x₁, x₂, y₁, y₂, z₁, z₂, a and a′=1; R₂ and R₂′=CF₃;and R₃ and R₃′=F.

In one embodiment of the perfluoroalkenyl-crosslinked polymericstructure the molar concentration of perfluoroalkenyl-crosslinked repeatunits is in the range of 0.5 to 5 mol-%.

In one embodiment, the perfluoroalkenyl-crosslinked polymer Π_(α) andΠ_(β) are the same and each further comprises PAVE repeat units. In afurther embodiment, PAVE ether is PMVE, PEVE, PPVE, PBVE, or acombination of two or more thereof.

In one embodiment of the perfluoroalkenyl-crosslinked polymer at least aportion of the fluoroalkenyl repeat units are branched fluoroalkenylrepeat units. Suitable fluoroalkenyl repeat units include but are notlimited to those derived from tetrafluoroethylene (TFE),hexafluoropropylene (HFP), vinylidene fluoride (VF₂), andperfluorodimethyldioxole (PDD). Particularly suitable are combinationsof fluoroalkenyl repeat units such as such as HFP with VF₂, and TFE withPDD.

The perfluoroalkenyl-crosslinked polymer exhibits a high degree ofthermal and hydrolytic stability. The properties of a shaped articleformed thereof are observed to vary desirably little upon heating saidshaped article from room temperature to 350-390° C. Hydrolytic stabilityat 325° C. is excellent.

In another aspect, the invention provides for a direct crosslinkingprocess comprising forming a reaction mixture by adding Cl—F, at atemperature in the range of room temperature to 100° C., to a firstcyano-functionalized polymer and a second cyano-functionalized polymer,which may be the same or different, each said polymer comprising abackbone chain, and wherein each said backbone chain comprisesfluoroalkylene repeat units optionally substituted by ether oxygen, anda molar concentration in the range of a molar concentration of 0.5 to 50mol-% of repeat units represented by Structure II

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; andR₃ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;with the proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saidcyano-functionalized polymer has more than two vinyl hydrogens attachedthereto; and, subjecting said reaction mixture to heating to atemperature in the range of 250 to 300° C.; with the proviso that saidfirst and second cyano-functionalized polymers can be the same ordifferent.

While not strictly necessary, it is highly preferred that in the directcrosslinking process, the cyano-functionalized polymer first be added toa vessel, the vessel be evacuated, and then the Cl—F introduced,followed by heating to 250 to 300° C.

Some embodiments of the process include those in which three or moredifferent polymers represented by Structure II are combined and reactedtogether to form the direct-crosslinked polymer.

In a further aspect, to further enhance the thermal and chemicalstability in the thus formed crosslinked polymer, the directcrosslinking process further comprises the steps of removing residualCl—F following the step of heating to 250 to 300° C., followed byfurther heating the thus formed crosslinked polymer to a temperature inthe range of >300 to 350° C.

In one embodiment heating in the range of >300-350° C. is effected in aninert atmosphere.

In one embodiment of the direct crosslinking process, in thecyano-functionalized polymer, x=1, y=1, z=1, a=1, R₂=CF₃; and R₃=F. Thisparticular repeat unit is derived from a monomer that shall be referredto herein as 8-CNVE.

In one embodiment of the direct crosslinking process, in thecyano-functionalized polymer, the molar concentration of repeat unitsrepresented by Structure II is in the range of 0.5 to 5 mol-%.

Cyano-functionalized polymers particularly suitable for use in thedirect crosslinking process by virtue of there being many embodimentsthat are solvent soluble, melt processible, or both, include but are notlimited to:

-   -   TFE/PAVE/8-CNVE copolymers wherein the PAVE repeat unit is PMVE,        PEVE, PPVE, PBVE, or a combination of two or more thereof,        wherein the repeat unit derived from the PAVE is present at a        concentration in the range of 18-49 mol %.    -   PDD/TFE/8-CNVE and PDD/8-CNVE copolymers wherein the PDD repeat        unit is present in the backbone at a concentration in the range        of 30 to 99 mol-%.    -   HFP/VF₂/8-CNVE copolymers wherein the HFP repeat unit is present        in the backbone at a concentration in the range of 15 to 50        mol-%.    -   HFP/TFE/8-CNVE copolymers wherein the HFP repeat unit is present        in the backbone at a concentration in the range of 25 to 35        mol-%.

In one embodiment, the direct crosslinking process comprises forming areaction mixture by adding Cl—F, at a temperature in the range of roomtemperature to 100° C., to an evacuated vessel containing acyano-functionalized polymer comprising a backbone chain comprisingrepeat units of tetrafluoroethylene, perfluoromethylvinyl ether, and amolar concentration in the range of 0.5 to 5 mol-% of repeat unitsrepresented by Structure VI

wherein said cyano-functionalized polymer has no crystalline meltingpoint above 180° C. that is associated with a latent heat of meltinggreater than 1 J/g; subjecting said reaction mixture to heating to atemperature in the range of 250 to 300° C.; removing residual Cl—Ffollowing the step of heating to 250 to 300° C., followed by furtherheating the polymer to a temperature in the range of >300 to 350° C. inan inert atmosphere.

In still another aspect, the present invention provides an imageablearticle comprising a substrate having a surface, and an imageable filmdisposed upon said substrate, said imageable film comprising one or moredichloroamino-functionalized polymers having a backbone chain comprisingfluoroalkylene repeat units optionally substituted by ether oxygen, anda molar concentration in the range of a molar concentration of 0.5 to 50mol-% of repeat units represented by Structure I

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; R₃is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; withthe proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saiddichloroamino-functionalized polymer has more than two vinyl hydrogensattached thereto; and, wherein said dichloroamino-functionalized polymerhas no crystalline melting point above 180° C. that is associated with alatent heat of melting greater than 1 J/g.

The imageable film is conveniently deposited upon the surface of thesubstrate by solution or melt coating. One preferred method ofdeposition is by spin-coating a solution onto a substrate followed byevaporative extraction of the solvent to prepare a film of a thicknessin the range of 0.2 to 3 micrometer, preferably 0.5 to 1 micrometer.

In one embodiment of the imageable article, in thedichloroamino-functionalized polymer, x=1, y=1, z=1, a=1, R₂=CF₃; andR₃=F.

In one embodiment of the imageable article, in thedichloroamino-functionalized polymer, the molar concentration of repeatunits represented by Structure I is in the range of 0.5 to 5 mol-%. In afurther embodiment of the imageable article, in thedichloroamino-functionalized polymer, the molar concentration of repeatunits represented by Structure I is in the range of 3 to 5 mol-%.

In one embodiment of the imageable article, thedichloroamino-functionalized polymer further comprises repeat units ofperfluoroalkyl vinyl ether (PAVE). In a further embodiment of theimageable article, in the dichloroamino-functionalized polymer, the PAVEis perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether(PEVE), perfluoropropyl vinyl ether (PPVE), perfluorobutyl vinyl ether(PBVE), or a combination of two or more thereof.

In one embodiment of the imageable article, in thedichloroamino-functionalized polymer at least a portion of thefluoroalkylene repeat units are branched fluoroalkylene repeat units.Suitable fluoroalkylene repeat units include but are not limited tothose derived from tetrafluoroethylene (TFE), hexafluoropropylene (HFP),vinylidene fluoride (VF₂), and perfluorodimethyldioxole (PDD).Particularly suitable are combinations of fluoroalkylene repeat unitssuch as such as HFP with VF₂, and TFE with PDD.

Suitable dichloroamino-functionalized polymers of which many embodimentsare solvent soluble, melt processible, or both, include but are notlimited to:

-   -   TFE/PAVE/8-CF₂NCl₂VE copolymers wherein the PAVE repeat unit is        PMVE, PEVE, PPVE, PBVE, or a combination of two or more thereof,        wherein the repeat unit derived from the PAVE is present at a        concentration in the range of 18-49 mol %.    -   PDD/TFE/8-CF₂NCl₂VE and PDD/8-CF₂NCl₂VE copolymers wherein the        PDD repeat unit is present in the backbone at a concentration in        the range of 30 to 99 mol-%.    -   HFP/VF₂/8-CF₂NCl₂VE copolymers wherein the HFP repeat unit is        present in the backbone at a concentration in the range of 15 to        50 mol-%.    -   HFP/TFE/8-CF₂NCl₂VE copolymers wherein the HFP repeat unit is        present in the backbone at a concentration in the range of 25 to        35 mol-%.

In one embodiment of the imageable article, thedichloroamino-functionalized polymer has no melting point above 150° C.that is associated with a latent heat of melting greater than 1 J/g.

Substrates suitable for use in the imageable article include metal,glass, and inorganic substrates particularly those of interest toelectronic, semiconductor, and optical applications such as silicon,gallium arsenide, aluminum gallium arsenide, indium phosphide, gold,copper, aluminum, potassium titanyl phosphonate, lithium niobate,sapphire, silica, and titanium dioxide. A preferred substrate issilicon. Applications in photolithography, photovoltaics. electrowettingand microlens arrays, are contemplated for the imageable article.

In one embodiment, the imageable article comprises a silicon substratehaving a surface, and an imageable film of a thickness in the range of0.5 to 1.5 micrometers thick disposed upon said surface, said imageablefilm comprising a solvent soluble dichloroamino-functionalized polymercomprising repeat units of tetrafluoroethylene, a molar concentration inthe range of 40 to 45 mol-% of perfluorodimethyldioxole repeat units,and a molar concentration in the range of 3 to 5 mol-% of repeat unitsrepresented by Structure V

wherein said dichloroamino-functionalized polymer has no crystallinemelting point above 150° C. that is associated with a latent heat ofmelting greater than 1 J/g, with the proviso that saiddichloroamino-functionalized polymer is soluble in a fluorinatedsolvent.

In a further aspect the invention provides a method comprising imagewiseexposing an imageable article to ultra-violet light at least a portionof which lies in the wavelength range from 200 to 425 nanometers; and,subjecting the thus imagewise exposed imageable article to imagedevelopment, thereby producing an imaged article; wherein said imageablearticle comprises a substrate having a surface, and an imageable filmdisposed upon said substrate, said imageable film comprising one or moredichloroamino-functionalized polymers having a backbone chain comprisingfluoroalkylene repeat units optionally substituted by ether oxygen, anda molar concentration in the range of a molar concentration of 0.5 to 50mol-% of repeat units represented by Structure I

where x is an integer in the range of 0 to 3, y is an integer in therange of 0 to 6, and z is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; R₃is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen; withthe proviso that y and z cannot both be zero; and, with the furtherproviso that no repeat unit in the backbone chain of saiddichloroamino-functionalized polymer has more than two vinyl hydrogensattached thereto; and, wherein said dichloroamino-functionalized polymerhas no crystalline melting point above 180° C. that is associated with alatent heat of melting greater than 1 J/g.

An imageable article suitable for the imagewise exposure method of thepresent invention can act as a negative photoresist when imagewiseexposed using UV light in the wavelength region from 200 to 425 nm,preferably 250 to 370 nm. As has been discussed supra and demonstratedin the specific embodiments infra, exposure of thedichloroamino-functionalized polymer cause it to undergo crosslinking toform the azo-crosslinked polymer. When a suitable imageable article isimagewise exposed to UV, the area of the imageable surface of a suitableimageable article that is exposed to the UV light will undergocrosslinking, while that area of the imageable surface that is maskedfrom the UV light will remain uncrosslinked. After imagewise exposure,the imageable article can be subject to development by exposing theimaged surface to a fluorinated solvent such asperfluoro-N-methylmorpholine, available as PF-5052 performance fluidfrom the 3M company. The unexposed portion of a suitable imageable filmwill dissolve in the solvent while the exposed portion will remainintact, thereby creating a negative image of the masking patternemployed in the imagewise exposure. If needed, all or a portion of theimage in its azo form as represented by Structure III can be convertedto the fluoroalkenyl-crosslinked represented by Structure IV by heatingto 200 to 350° C.

The thus prepared imaged article can then be employed in theapplications known in the art for imaged polymeric articles. Theseinclude photolithography and photovoltaics.

Substrates suitable for use in the imagewise exposure method disclosedherein include metal, glass, and inorganic substrates particularly thoseof interest to electronic, semiconductor, and optical applications suchas silicon, gallium arsenide, aluminum gallium arsenide, indiumphosphide, gold, copper, aluminum, potassium titanyl phosphonate,lithium niobate, sapphire, silica, and titanium dioxide. A preferredsubstrate is silicon.

In one embodiment of the imagewise exposure method hereof, a suitableimageable film is characterized by a thickness in the range of 0.2 to 3micrometers, preferably 0.5 to 1 micrometer.

While not demonstrated it is anticipated that films thicker than 0.2 to0.3 micrometers could be imaged as well since UV light was shown tofully penetrate and crosslink a polymer film 0.06 inch (1500 micronsthick) in Example 12. In one embodiment of the imagewise exposure methodhereof, in the dichloroamino-functionalized polymer of a suitableimageable film, x=1, y=1, z=1, a=1, R₂=CF₃; and R₃=F.

In one embodiment of the imagewise exposure method hereof, in thedichloroamino-functionalized polymer of the imageable film, the molarconcentration of repeat units represented by Structure I is in the rangeof 0.5-5 mol-%. In a further embodiment of the imagewise exposure methodhereof, in the dichloroamino-functionalized polymer of a suitableimageable film, the molar concentration of repeat units represented byStructure I is in the range of 3-5 mol-%.

In another aspect, the present invention provides an imaged articlecomprising a substrate having a surface, and a crosslinked coatingimagewise disposed upon said surface, said crosslinked coatingcomprising an azo-crosslinked polymer represented by Structure III

wherein each of Π_(α) and Π_(β) is a polymeric radical having a backbonechain comprising fluoroalkylene repeat units optionally substituted byether oxygen, and azo-crosslinked repeat units at a molar concentrationin the range of a molar concentration of 0.5 to 50 mol-%; where x₁ andx₂ each independently is an integer in the range of 0 to 3; y₁ and y₂each independently is an integer in the range of 0 to 6, and z₁ and z₂each independently is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;R₁′=(CF₂)_(a′)CFR₂′ where a′ is an integer in the range of 0 to 6, andR₂′ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;and, R₃ and R₃′ are each independently F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen; with the proviso that y₁ and z₁cannot both be zero; with the further proviso that y₂ and z₂ cannot bothbe zero; with the further proviso that no repeat unit in the backbonechain of said Π_(α) and Π_(β) polymeric radicals has more than two vinylhydrogens attached thereto; and, with the further proviso that Π_(α) andΠ_(β) can be the same or different.

In one embodiment, in the azo-crosslinked polymer of the imaged articlehereof, Π_(α) and Π_(β) are the same.

In an alternative embodiment, in the azo-crosslinked polymer of theimaged article hereof, Π_(α) and Π_(β) are different.

In one embodiment, in the azo-crosslinked polymer of the imaged articlehereof, Π_(α) and Π_(β) are the same, x=1, y=1, z=1, and a=1; R₂ andR₂′=CF₃; and R₃ and R₃′=F.

In one embodiment, in the azo-crosslinked polymer of the imaged articlehereof, the molar concentration of crosslinked repeat units asrepresented in Structure III is in the range of 0.5 to 5 mol-%. In afurther embodiment, in the azo-crosslinked polymer of the imaged articlehereof, the molar concentration of crosslinked repeat units asrepresented in Structure III is in the range of 3 to 5 mol-%.

In one embodiment, in the azo-crosslinked polymer of the imaged article,Π_(α) and Π_(β) are the same and each further comprises PAVE repeatunits. In a further embodiment, PAVE ether is PMVE, PEVE, PPVE, PBVE, ora combination of two or more thereof.

In one embodiment, in the azo-crosslinked polymer of the imaged articlehereof, at least a portion of the fluoroalkylene repeat units arebranched fluoroalkylene repeat units. Suitable fluoroalkylene repeatunits include but are not limited to those derived fromtetrafluoroethylene (TFE), hexafluoropropylene (HFP), vinylidenefluoride (VF₂), and perfluorodimethyldioxole (PDD). Particularlysuitable are combinations of fluoroalkylene repeat units such as such asHFP with VF₂, and TFE with PDD.

In a preferred embodiment of the imaged article hereof, theazo-crosslinked polymer represented by Structure III further comprisesrepeat units of TFE and PAVE wherein the repeat unit derived from thePAVE is present at a concentration in the range of 18-49 mol %. The PAVErepeat unit is PMVE, PEVE, PPVE, PBVE, or a combination of two or morethereof.

In an alternative preferred embodiment of the imaged article hereof, theazo-crosslinked polymer represented by Structure III further comprisesrepeat units of PDD and, optionally, TFE wherein the PDD repeat unit ispresent in the backbone at a concentration in the range of 30 to 99mol-%.

In an alternative preferred embodiment of the imaged article hereof, theazo-crosslinked polymer represented by Structure III further comprisesrepeat units of HFP and VF₂ wherein the HFP repeat unit is present inthe backbone at a concentration in the range of 15 to 50 mol-%.

In an alternative preferred embodiment of the imaged article hereof, theazo-crosslinked polymer represented by Structure III further comprisesrepeat units of HFP and TFE wherein the HFP repeat unit is present inthe backbone at a concentration in the range of 25 to 35 mol-%.

In one embodiment, the imaged article comprises a silicon substratehaving a surface, and a crosslinked coating imagewise disposed upon saidsurface, said crosslinked coating, of a thickness in the range of 0.5 to1.5 micrometers, comprising an azo-crosslinked polymer represented byStructure VII

wherein π is a polymeric radical having a backbone chain comprisingrepeat units of tetrafluoroethylene, a molar concentration in the rangeof 40 to 45 mol-% of perfluorodimethyldioxole repeat units, and a molarconcentration in the range of 3 to 5 mol-% of repeat units representedby Structure VII.

In one embodiment, the imaged article is in the form of a printedcircuit board. In an alternative embodiment, the imaged article is inthe form of a surface for electrowetting.

The invention is further described, but not limited by the followingspecific embodiments.

EXAMPLES Terminology and Materials Glossary

AFM Atomic Force Microscopy, performed using a Bruker Dimension 3100instrument with a Nanoscope IV controller. ATR Attenuated TotalReflectance spectroscopy in the infrared (IR) performed using a ThermoNicolet 6700 FT-IR equipped with a SensIR Durascope ™ IR Infraredspectroscopy IV Inherent viscosity MDR Moving Die Rheometer, MonsantoMDR 2000 UV Ultraviolet Radiation T_(g) Glass-transition temperature asdetermined using differential scanning calorimetry. (DSC)

Azo and fluoroalkenyl crosslinks made by joining two cyano groups werecounted as two units in the final crosslinked polymers. This is of greatconvenience when relating the mole % of cyano groups in a starting P—CNto the mole % of —N═N— and —CF2CF2-crosslinks in the final P—N═N—P orP—CF2CF2-P polymers.

Materials Used in Examples Cl—F chlorine monofluoride, Obtained fromAdvance Research Chemicals or synthesized, as indicated, infra. 8-CNVECF₂═CFOCF₂CF(CF₃)OCF₂CF₂CN Synthesized according to the method taught inEuropean Patent Application 729940, Sep. 4, 1996. i-8CNVECF₂═CFOCF₂CF₂CF₂OCF(CF₃)CN Prepared as taught in European PatentApplication 710645 May 8, 1996. FC-40 Fluorinert ® FC-40 3M Company HFPhexafluoropropylene, CF₃CF₂═CF₂ Obtained from DuPont HFPOCF₃CF₂CF₂OCF(CF₃)(C═O)OO(C═O)CF(CF₃)OCF₂CF₂CF₃ Prepared according toDimer the teachings of Peroxide U.S. Pat. No. 5,831,131 PF-5052perfluoro-N-methylmorpholine 3M Company PDD2,2-bis(trifluoromethyl)-4,5-difluoro-1,3-dioxole,  

Prepared according to the teachings of U.S. Pat. No. 4,409,393. PMVEPerfluoromethylvinylether, CF₃OCF═CF₂ Obtained from DuPont TFETetrafluoroethylene, CF₂═CF₂ Obtained from DuPont Vertrel ® XFCF₃CFHCFHCF₂CF₃ Obtained from DuPont VF₂ vinylidene fluoride, CH₂═CF₂Obtained from Solvay Solexis Inc. Krytox Perfluoropolyether surfactanthaving carboxylate end groups. Obtained from DuPont 157 FSLSample Preparation

Film samples were prepared using a laboratory hydraulic press. Aspecified weight of polymer was placed into a layered structureconsisting of steel sheet/Kapton® polyimide film/polymer sample/Kapton®polyimide film/steel sheet. The so-prepared layered structure was thenplaced between the platens of a Pasadena Hydraulics, Inc press. Unlessstated otherwise, polymer was piled on the Kapton® and then pressed downgiving a roughly circular piece generally 1 to 5″ in diameter and tensof mils thick. When it was desired to press a second film from the samepolymer sample that had been pressed into a previously prepared pressedfilm, the previously pressed film was first cut up into pieces and thepieces then pressed again, as described.

When molded specimens in the range of 0.060 to 0.160 inches thick werefabricated, the layered structure consisted of steel sheet/Kapton®polyimide film/a pile of polymer centered in a rectangular mold/Kapton®polyimide film/steel sheet, the mold consisting of a stainless steelsheet with a rectangular hole cut in the center. Extra polymer(flashing) was trimmed from the edges of the molded parts.

The pressing conditions are expressed hereinin the following manner:time (min)/temperature(° C.)/ram force(lbs). The “time” refers to thedwell time of the polymer sample at the “temperature” indicated, and atthe exerted ram force indicated. Thus the expression 3 min/95° C./0 lbsmeans that the sample was held for 3 min. with the platens set at 95° C.and with the platens closed but exerting 0 lbs of force.

Analysis

Spectroscopy

The chemistry that takes place in the processes disclosed herein occursat the terminal functional group of the 8-CNVE monomer unit, asdescribed infra. The 8-CNVE can be tracked in the IR by an ether peak at1036 cm⁻¹. The monomer unit derived from PMVE is characterized by an IRabsorption peak at 889 cm⁻¹. There is no evidence that any of thechemistry described herein involved monomer units derived from PMVE.That is, the monomer groups are believed to be inert. The ratio of thepeak intensities at 1036 cm⁻¹ and 899 cm⁻¹ was then taken as a means formeasuring the extent of reaction of the CN functional group.

The IR spectrum was determined using a Thermo Nicolet 6700 FT-IRequipped with a SensIR Durascope™. The Durasope™ was a single bounceDiamond Attenuated Total Reflectance (DATR) accessory. A backgroundspectrum of the DATR was acquired before each sample. The DATR was wipedclean after each sample. The sample was placed in contact with thediamond. The sample was then pressed against the diamond using thesample press. The spectrum was collected and compared to the background.A baseline and ATR correction were applied to the spectrum using NicoletOmnic® software. The spectrum was imported to G/AI 8.0 Spectroscopysoftware. In G, a Fourier deconvolution algorithm was applied using agamma of 6. The peaks of interest were integrated within G. The peakheight and areas were determined.

After treatment with Cl—F, any given specimen was purged using N₂ toremove any residual Cl—F or Cl₂. Purging was accomplished bytransferring the Cl—F-treated specimen from the autoclave to a ziplockplastic bag or a glass bottle, the bag or bottle was sealed, and placedin a fume hood. With the specimen in the fume hood, a small opening wasmade in the bag or bottle, and a tube carrying nitrogen was placedtherein. The nitrogen purge was continued for at least several hours.

Polymer Compositional Designations

Throughout the Examples, polymers are referred to variously asP—CF₂NCl₂, P—CF₂N═NCF₂—P, and P—CF₂CF₂—P, as well as mixtures thereof.In every instance, the given designation is intended to indicate thespecies that predominantly affects the measured properties, mechanical,thermal, thermomechanical, and spectroscopic. That is, for example, asshown infra, P—CF₂NCl₂ converts to P—CF₂CF₂—P via mixtures of P—CF₂NCl₂,P—CF₂N═NCF₂—P and P—CF₂CF₂—P and a process may stop at a mixture stage.Thus a designation such as P—CF₂NCl₂ is not intended to suggest that theindicated species is present in neat form. In many of the examples, itis strongly believed that some other species than that indicated ispresent at undetermined concentration.

Inherent Viscosity

Inherent Viscosity (IV) was determined using a solution of 0.1 g ofpolymer in 100 g of FLUTEC™ PP11 perfluorocarbon fluid (F2 ChemicalsLtd., Preston, UK) at 30° C., except where otherwise noted.

Example 1 Progression of Cl—F Chemistry and Crosslinking with Time andTemperature

A. Polymer Synthesis:

A perfluoroelastomer containing copolymerized monomers of TFE, PMVE, and8CNVE was prepared as follows. Three aqueous streams were each fedcontinuously to a 2 liter, mechanically stirred, water jacketed,stainless steel autoclave at a rate of 162 cc/hr. The first streamconsisted of a solution of 12.8 g ammonium persulfate in 5 kg ofdeionized, deaerated water. The second stream consisted of 249.5 g ofF(CF₂)₅—CH₂O—PO₂(OH)(NH₄) surfactant and 41.6 g of Krytox® 157FSLsurfactant in 5 kg of deionized, deaerated water. The third streamconsisted of a solution of 77.0 g disodium hydrogen phosphateheptahydrate in 5 kg of deionized, deaerated water. Using a diaphragmcompressor, a mixture of TFE (145.5 g per hour (g/hr)) and PMVE (83.6g/hr) was fed at a constant rate. Using a syringe pump, 8-CNVE was fedto the reactor at a rate of 4.20 milliliters per hour. The temperaturewas maintained at 85° C., and a pressure at 4.1 MPa (600 psig) wasmaintained throughout the reaction. The polymer emulsion was removedcontinuously by means of a letdown valve and the unreacted monomers werevented. Eight liters of deionized water was added per liter of emulsionand then 1% NaOH solution added until its pH was 6.9. After pHadjustment, the emulsion was coagulated with magnesium sulfateheptahydrate and washed with deionized water. The polymer was dried at70° C. for 48 hours. The polymer had an inherent viscosity of 0.48measured in a solution of 0.1 g polymer in 100 g FLUTEC™ PP11perfluorocarbon fluid (F2 Chemicals Ltd., Preston, UK) at 30° C.

T_(g) was determined to be 9.5° C. by DSC. No melting endotherm wasobserved.

Composition was found to be 57.61 wt ° A) TFE, 35.60 wt ° A) PMVE, and6.79 wt % 8-CNVE [71.3 mole ° A) TFE, 26.5 mole ° A) PMVE, 2.2 mole ° A)8-CNVE] by FTIR. This polymer will be referred to herein as P1-CN.

B. Film

5 g of the P1-CN polymer prepared in Example 1A were placed between theplatens of a hydraulic press as described, supra, and processed asfollows: 3 min/95° C./0 lbs followed by 3 min/95° C./5,000 lbs, followedby release of pressure and cooling. The resulting film was roughlycircular with a ca. 6.4 cm diameter. Thickness ranged from 0.003 to0.0046 inches.

An ATR spectrum taken of the P1-CN film found the area of the 1036 cm⁻¹band corresponding to copolymerized 8-CNVE to be 1.11 times the area ofthe 889 cm⁻¹ band corresponding to copolymerized PMVE. The intensityratio of the 1036 cm⁻¹ band relative to the 889 cm⁻¹ band was observedto decrease as the reaction of Cl—F with the —CN group in copolymerized8-CNVE progressed.

A thin strip weighing 0.0878 g was cut from the thus prepared film. Thisstrip was placed into a vial with 2 g of PF-5052 liquid. The vial wassealed and subject to rolling on a roll mill at 120 rpm for about 41hours until no further dissolution was apparent by visual inspection.After rolling, the contents of the vial were visually examined. The filmappeared to have partially dissolved, leaving a residue of numerous gelparticles suspended in the solution.

Three small 1.5″ long dog-bone-shaped strips of the film were pulled at23° C. at 0.5 inch/minute with the sample gauge length of 0.86 inchesusing an Instron® Universal Testing Machine. Tensile strength was anaverage 640 psi at 300% elongation to break.

Additional samples of the P1-CN polymer prepared in Example 1A wereprepared for use in Part C, below. Each 5 g sample was hot pressed for 3min/95° C./0 lbs followed by 3 min/95° C./5,000 lbs, followed by releaseof pressure and cooling. The films so prepared were roughly circular,˜2.5″ in diameter and varied from about 0.0030 to 0.0046″ inches inthickness.

C. Reaction with Cl—F

Example 1a Treatment with Cl—F for 7 Hours at 70° C.

A 400 ml Hastelloy® autoclave was loaded with 5.6 g Cl₂ (0.08 mole) and6.1 g of 25 mole % F₂ (0.05 mole F₂) in N₂. This mixture was heated to250° C. over a period of ˜1.5 hours and then held at 250° C. for 1 hour.No exotherm was observed. The product was believed to be anapproximately 1:3 Cl₂:Cl—F mixture.

Gambaretto et al., J. Fluorine Chem. 7, 569 (1976) showed nearquantitative yield of Cl—F when F₂ plus a slight excess of Cl₂ werepassed through a 250° C. tube furnace with a 100 second contact time.

One of the approximately 2.5″ diameter film specimens of the P1-CN filmprepared in Example 1-B was hand-pressed down on a Teflon® film so thatthe specimen exhibited enough adhesion to hold the film specimen inplace as it was being lowered into a horizontal position into a 400 mlHastelloy® autoclave. The autoclave was sealed, evacuated, and thenpressured to 40 psig with the Cl₂/Cl—F mixture prepared supra.

The autoclave was heated for 7 hours at 70° C. After cooling theautoclave, the polymer film was recovered, transferred to a tightcontainer, the container moved to a fume hood, the container opened,tubing inserted in the open mouth of the container, and a slow flow ofpurging nitrogen run through the container for 21 hours to remove anyresidual Cl₂ or Cl—F. The thus treated film is herein designatedP1-CF₂NCl₂-1a.

An ATR spectrum was taken of the side of the P1-CF₂NCl₂-1a film awayfrom the Teflon® sheet. The 1036 cm⁻¹ band had decreased to 0.20× thearea of the 889 cm⁻¹ peak. A new absorption band at 960 cm⁻¹ was alsoobserved, with an area 0.23× the area of the 889 cm⁻¹ peak. Since Hyneset. al., op.cit., reported a strong band at 968 cm⁻¹ in the gas phase IRof CF₃CF₂CF₂NCl₂, the new band observed herein at 960 cm⁻¹ can beassigned to the P1-CN polymer wherein the CN groups have been convertedto CF₂NCl₂ groups by the Cl—F.

A 0.0737 g strip of the thus prepared film of P1-CF₂NCl₂-1a was rolled,as in Example 1 B, with 2 g of PF-5052 solvent until there was no longerany visual change By visual examination, it was observed that the resultwas a hazy solution having fewer gel particles than observed for thesolution of P1-CN, described supra, but still too many to count.

Two small dog-bone-shaped strips of the P1-CF₂NCl₂-1a film were pulledon an Instron Machine, as described supra, exhibiting an average tensilestrength of 370 psi at 330% elongation to break.

Example 1b Treatment with Cl—F for 7 Hours at 90° C.

The materials and procedures employed in Example 1a were repeated exceptthat the temperature of the autoclave was 90° C. The polymer film soprepared is herein designated P1-CF₂NCl₂-1b

An ATR spectrum was taken of the P1-CF₂NCl₂-1 b film. The intensityratio of the 1036 cm⁻¹ absorption to the 889 cm⁻¹ absorption was 0.2243.The intensity ratio of the 960 cm⁻¹ absorption to that of the 889 cm⁻¹absorption was 0.1265.

A 0.1247 g strip of the P1-CF₂NCl₂-1b film was rolled with PF-5052, asin Example 1a. The resultant mixture was observed to consist of a massof soft gel. The thus treated strip of P1-CF₂NCl₂-1b film was observedto have swollen to many times its original size, but still had a faintresemblance to the starting piece of film. When, however, an attempt wasmade to pick up the swollen P1-CF₂NCl₂-1 b film with tweezers, the tinespassed right through without hitting anything solid enough to be pickedup.

A 1 gram sample of the P1-CF₂NCl₂-1b film was cut up and pressed betweenthe platens of the hydraulic press, as described supra, in the followingmanner: 3 min/95° C./0 lbs then 3 min/95° C./5,000 lbs, followed byrelease of pressure and cooling. The resulting film was homogeneous inappearance, flat, and approximately circular with a diameter of 44 mm.The thus prepared P1-CF₂NCl₂-1b film was not noticeably different infilm formability from the P1-CF₂NCl₂ polymer used to prepare theP1-CF₂NCl₂-1a film.

Example 1c Treatment with Cl—F for 7 Hours at 100° C.

The procedures and materials employed in Example 1a were repeated exceptthat the autoclave temperature was 100° C. The film so treated is hereindesignated P1-CF₂NCl₂/Azo-1c to indicate that the properties thereofsuggest that some amount of crosslinking occurred during the heating.

An ATR spectrum was taken of the P1-CF₂NCl₂/Azo-1c film. The intensityratio of the 1036 cm⁻¹ absorption to the 889 cm⁻¹ absorption was 0.1877.The intensity ratio of the 960 cm⁻¹ absorption to that of the 889 cm⁻¹absorption was 0.1398.

A 0.1175 g strip of the P1-CF₂NCl₂/Azo-1c film was rolled with PF-5052,as in Example 1a. The resultant mixture was observed to consist of amass of gel indistinguishable from the similarly treated P1-CF₂NCl₂-1 bfilm.

A 1 gram sample of the P1-CF₂NCl₂/Azo-1c film was cut up and pressed inthe hydraulic press, as described supra, in the following manner: 3min/95° C./0 lbs then 3 min/95° C./5,000 lbs, followed by release ofpressure and cooling. The resulting film was a flat and approximatelycircular with an approximately 44 mm diameter. Some roughness, lines andholes in the pressed film were observed.

Example 1d Treatment with Cl—F for 7 Hours at 130° C.

The materials and procedures of Example 1a were repeated except that theautoclave temperature was 130° C. The film so prepared is hereindesignated polymer P1-CF₂NCl₂/Azo-1d.

An ATR spectrum was taken of the P1-CF₂NCl₂/Azo-1d film. The intensityratio of the 1036 cm⁻¹ absorption to the 889 cm⁻¹ absorption was 0.03.The intensity ratio of the 960 cm⁻¹ absorption to that of the 889 cm⁻¹absorption was 0.19.

A 0.1802 g strip of the P1-CF₂NCl₂/Azo-1d film was rolled with PF-5052,as in Example 1a. The film specimen was observed to have retained itsintegrity, and had absorbed 0.6239 g of the solvent, for a 440% increasein weight.

A 1 g sample of the P1-CF₂NCl₂/Azo-1d film was cut up and pressed in thehydraulic press, as described supra, in the following manner: 3 min/95°C./0 lbs then 3 min/95° C./5,000 lbs, followed by release of pressureand cooling. The resulting film exhibited rough texture, lines, andholes.

Example 1e Treatment with Cl—F for 7 Hours at 70° C. and then 2 Hours150° C.

The materials and procedures of Example 1a were repeated except that theautoclave temperature was first held for 7 hours at 70° C., and raisedto 150° C. and held for 2 hours. The film so prepared is hereindesignated polymer P1-CF₂NCl₂/Azo-P1-1e.

An ATR spectrum was taken of the P1-CF₂NCl₂/Azo-P1-1e film. Theintensity ratio of the 1036 cm⁻¹ absorption to the 889 cm⁻¹ absorptionwas 0.07. The intensity ratio of the 960 cm⁻¹ absorption to that of the889 cm⁻¹ absorption was 0.10.

A 0.0345 g strip of the P1-CF₂NCl₂/Azo-P1-1e film was rolled withPF-5052, as in Example 1a. The film specimen was observed to haveretained its integrity, and had absorbed 0.1637 g of the solvent, for a370% increase in weight.

Two small dog-bone-shaped strips cut from this film were pulled on anInstron as described supra. Average tensile strength was 1000 psi at320% elongation to break.

Example 1f Treatment with Cl—F for 7 Hours at 70° C., 2 Hours 150° C.,and 2 Hours at 200° C. Additional Heating Under N₂ at 300 and 350° C.

The materials and procedures of Example 1a were repeated except that theautoclave was first heated for 7 hours at 70° C., then the temperaturewas raised to 150° C., and held for an additional 2 hours. Thetemperature was then raised to 200° C., and held for an additional 2hours. The film so prepared is herein designated polymerP1-Azo-P1/P1-CF₂CF₂-P1-1f.

An ATR spectrum was taken of the P1-Azo-P1/P1-CF₂CF₂-P1-1f film. Theintensity ratio of the 1036 cm⁻¹ absorption to the 889 cm⁻¹ absorptionwas 0.00. The intensity ratio of the 960 cm⁻¹ absorption to that of the899 cm⁻¹ absorption was 0.00. A new absorption peak at 970 cm⁻¹ wasobserved. The intensity of the 970 cm⁻¹ absorption to that at 889 cm⁻¹was 0.08.

A 0.0358 g strip of the P1-Azo-P1/P1-CF₂CF₂-P1-1f film was rolled withPF5052, as in Example 1a. The film specimen was observed to haveretained its integrity, and had absorbed 0.0822 g of the solvent, for a130% increase in weight. There was minimal change in the appearance ofthe strip.

Two small dog-bone-shaped strips of the P1-Azo-P1/P1-CF₂CF₂-P1-1f filmwere pulled on an Instron, described supra. Average tensile strength was1300 psi at 80% elongation to break.

A 0.2573 g strip of the P1-Azo-P1/P1-CF₂CF₂-P1-1f film was furtherheated for 2 hours under nitrogen at 300° C. reducing its weight to0.2474 g. The thus treated film is herein designated P1-CF₂CF₂-P1-1f. AnATR spectrum of the thus treated film strip showed that the 970 cm⁻¹/889cm⁻¹ absorption strength ratio was 0.30. Rolling a 0.0933 g piece of theP1-CF₂CF₂-P1-1f film with 1.5 g of PF-5052 caused it to increase inweight to 0.2503 g (168% wt gain).

An additional 0.2480 g strip of P1-Azo-P1/P1-CF₂CF₂-P1-1f film wasfurther heated for 2 hours under nitrogen at 350° C. causing its weightto decrease to 0.2419 g. An ATR spectrum of the thus treated film stripshowed that the 970 cm⁻¹:899 cm⁻¹ absorption strength ratio was 0.30.Rolling an 0.0706 g piece of this film with 1.5 g of PF-5052 caused itto increase in weight to 0.2132 g (201% weight gain).

Example 2 Photochemical Conversion to Azo Crosslink Followed by ThermalConversion to —CF₂CF₂— Crosslink

A 5 g film sample of the P1-CN polymer was treated as in Example 1a. Thefilm so prepared will be designated herein P1-CF₂NCl₂-2.

An ATR spectrum showed the 1036 cm⁻¹:889 cm⁻¹ absorption strength ratioto be 0.32, and the 960 cm⁻¹:899 cm⁻¹ absorption strength ratio to be0.09.

A small section of the P1-CF₂NCl₂-2 film was cut off with scissors andplaced in a quartz box 3.8″ square by 1.3″ high, under a slow, steady N₂purge. A Rayonet UV bulb, catalog R.P.R 2537A, was brought up to thequartz box, bringing the bulb within about an inch and a half of theP1-CF₂NCl₂-2 film, a distance at which the UV bulb delivered about 0.17milliwatts/cm². The film, to be herein designated as P1-Azo-P1-2, wasrecovered after 24 hrs of UV exposure. An ATR spectrum of theP1-Azo-P1-2 film showed the 1036 cm⁻¹:889 cm⁻¹ absorption strength ratioto be 0.31. The 960 cm⁻¹ absorption band was not detectable; and, the970 cm⁻¹ band was not observed.

The thus prepared P1-Azo-P1-2 film was divided into a 0.2180 g piece anda 0.1725 g piece. Rolling the 0.2180 g piece with 2 g of PF-5052 solventcaused its weight to increase to 0.4220 g (a 94% weight gain) ratherthan go into solution.

The 0.1725 g strip of P1-Azo-P1-2 was heated for 68 hours in a 225° C.oven under N₂. The film specimen so prepared is herein designatedP1-Azo-P1/P1-CF₂CF₂-P1-2. An ATR spectrum of theP1-Azo-P1/P1-CF₂CF₂-P1-2 film showed the 1036 cm⁻¹:889 cm⁻¹ absorptionstrength ratio to be 0.26. The 960 cm⁻¹ absorption band was again notdetectable; and, the 970 cm⁻¹ band characteristic of the—CF2CF2-crosslink had appeared, and the absorption strength ratio of the970 cm⁻¹: 889 cm⁻¹ absorption bands was 0.05.

The thus prepared P1-Azo-P1/P1-CF₂CF₂-P1-2 film was heated again, thistime for 1 hour at 300° C. under N₂. An ATR spectrum of the thus treatedfilm showed the 1036 cm⁻¹:889 cm-1 absorption strength ratio to be 0.16and the 970 cm⁻¹:889 cm⁻¹ absorption strength ratio to be 0.06. Afterheating, the thus prepared film weighed 0.1696 g. When rolled with 2 gPF-5052 the weight increased to 0.4010 g (a 136% weight gain).

Example 3 Reaction-Induced Changes in UV Spectrum

A disc about ¾ in. diameter by about 0.035 in. thick was cut out of theP1-CF₂NCl₂-1a sheet. The UV spectrum showed an absorption peak at 291nm, close to the 294 to 298 nm absorption peaks reported by Hynes etal., op.cit., for compounds such as CF₃CF₂CF₂NCl₂ (294 nm) andCl₂NCF₂CF₂CF₂NCl₂ (298 nm). The P1-CF₂NCl₂-1a film was then subject toexposure to UV irradiation according to the procedure of Example 2. Thefilm thereby prepared, herein designated P1-Azo-P1-3 was recovered afterabout 94 hrs of UV exposure, and its UV spectrum was taken. The band at291 nm had entirely disappeared. Both sides of the film showed the sameUV spectrum consistent with good penetration of the light though thefilm and complete reaction.

A model compound represented by Structure VIIIClCF₂CFClOCF₂CF(CF₃)O(CF₂)₃N═N(CF₂)₃OCF(CF₃)CF₂OCFClCF₂Cl  VIIIwas prepared as follows: Neat chlorine gas was bubbled at 5-10° C.through 77.8 g of 8-CNVE. The reaction was stopped when the conversionof 8-CNVE to CF₂ClCFClOCF₂CF(CF₃)OCF₂CF₂CN was almost complete. Theresulting material was distilled to give the desired product as a clear,colorless liquid, yield 80 g (87%), by 85° C./180 mm. ¹⁹F NMR (CDCl₃):−71.3 ppm (t, J=5.5 Hz, 2F), −77.5 (m, 1F), −80.2 (d, J=8.3 Hz, 3F),−82.3 to −85.8 (m, 4F), −108.8 (t, J=4.2 Hz, 2F), −145.6 (m, Br, 1F).Anal. Calc. for C₈Cl₂F₁₃NO₂: C, 20.89; Cl: 15.42; F: 53.69. Found C,20.87; Cl, 14.50; F, 53.23. MS: [Parent-CF2CF2CN]: Calc. 332.9132.Found: 332.9166.

A 20 g sample of the thus prepared CF₂ClCFClOCF₂CF(CF₃)OCF₂CF₂CN wasadded to a monel cylinder chilled to −50° C. in dry ice/CHCl₃. Asolution of 3 ml of BrF₃ dissolved in 10 ml of CF₂ClCCl₂F was added. Thecylinder was closed and allowed to warm to room temperature. After twodays at room temperature, the reaction mixture was poured onto 100 ml of10% sodium hydroxide in water. The organic layer was washed with water,dried over MgSO₄ and evaporated down to 19.5 g of oil. This and anearlier run were combined and distilled affording,

Cut #1 bp 20.5° C./0.3 mm 5.87 g Cut #2  bp 97° C./0.3 mm 18.6 g Cut #3pot residue   2 gFluorine NMR of Cut #2: −71.3 ppm (CF₂Cl), −77.3 (CFCl), −80.4 to −85.6(CF₂CF(CF₂OCF₂), −108.8 (CF₂CF₂N═), 127.7 (CF₂N═). Anal. Calc. forC₁₆Cl₄F₃₀N₂O₄: C, 19.30; N, 2.81; F, 57.23; Cl 14.24. Found C, 18.97; N,3.58; F, 55.03; Cl, 3.87. GC on an Agilent, DB-5MS UI. 30 m×0.25 mm, 1μm column, heating 10° C./min to 300° C. and then holding at 300° C.gave a major peak with a 13 minute retention time. Using a lowresolution GCT Mass Spectrometer to analyze the major GC peak a M+1 peakwas observed with the help of isobutane chemical ionization, the M+1peak having a mass of 994.7 vs. 994.82059 calculated forC₁₆Cl₄F₃₀N₂O₄+H. Taking the mass spectrum of the same GC peak using ahigher resolution LTQ Orbitrap Mass Spectrometer with chemicalionization, a M-F peak was observed at mass 974.8153 versus a mass of974.8144 calculated for C₁₆O₄N₂Cl₄F₂₉.

UV spectroscopy of the model compound of Structure VIII thus preparedshowed a molecular extinction coefficient of 23.13 at 379.5 nm.

Repeating UV spectroscopy on the P1-Azo-P1-3 film, but at very highgain, with baseline correction and smoothing, a new weak peak around 382nm appeared, corresponding to the azo structure in the model compound.

Example 4 NMR Evidence for —CF₂₂— Crosslink

A. Preparation of 77:23 Mole % Poly(TFE/8-CNVE).

A 400 ml autoclave was loaded with 150 ml deionized water, 3 g ofC₈F₁₇COONH₄, 0.15 g Na₂HPO₄, 0.3 g ammonium persulfate, and 25 g of8-CNVE. The autoclave was cooled, evacuated, and further loaded with 15g TFE. Shaking the autoclave at 70° C., pressure in the autoclave peakedat 178 psig and then decreased to 9 psig 1,030 minutes later, thepressure drop indicating near complete reaction of the TFE. The product,a hazy emulsion, was frozen on dry ice, thawed, and solids filtered off.The solids were rinsed in the filter with 2000 ml water, 500 mlmethanol, and 380 ml acetone while working with a spatula to break upchunks. Sucking dry gave 28.7 g of product that gave partial solutionwith soft gel when mixed with PF-5052. Fluorine NMR in the melt at 320°C. found 77:23 mole % poly(TFE:8-CNVE). GPC analysis in Flutec foundMn=16,000 and Mw=41,000. The polymer so-prepared is herein designatedP2-CN

B. Treatment of P2-CN with Cl—F.

A 5 g sample of the P2-CN was pressed 3 min/90° C./0 lb, 3 min/90°C./5000 lb to make a film which was loaded into a 400 ml autoclavemounted on a Teflon® sheet, as described supra. The autoclave wasevacuated and filled to 40 psig with the Cl₂/Cl—F mixture prepared inExample 1. The resulting reaction mixture was heated for 16 hrs at 70°C. affording a film product herein designated P2-CF₂NCl₂-4.

C.

A 0.0717 g slice of the P2-CF₂NCl₂-4 film was heated for 1 hour at 300°C. under N₂ causing its weight to decrease to 0.0646 g. The film soprepared, herein designated P2-CF₂CF₂-P2-4, was cut into two pieces.

Rolling a 0.0304 g piece of the P2-CF₂CF₂-P2-4 film with 2 g of PF-5052increased its weight to 0.0430 g (41% weight gain).

D.

The fluorine NMR spectrum of P2-CN in the melt at 320° C. exhibited apeak at −105 ppm corresponding to the fluorine of the reactive CF₂CNmoiety, and a peak at −139 ppm corresponding to the bolded fluorine inthe unreacting CFCF₃. The progress of the reaction herein was followedby tracking the change in the integrated intensity of the −105 ppmversus that of the −139 ppm peak.

NMR at 160° C. of the P2-CF₂CF₂—P2-4 film exhibited a new CF2 peakappearing at −98 ppm while the −105 ppm peak exhibited a loss ofintegrated intensity of about 62%. The integrated intensity of the −98ppm was approximately equal to the loss of integrated intensityexhibited by the −105 ppm peak.

Comparative Example a Small Molecule Analog

A 1 gram sample of model compound represented by Structure VIII preparedsupra, was heated in an autoclave for 1 hour at 300° C. in 50 ml ofperfluorooctane, followed by cooling and extraction of residualperfluorooctane. Fluorine NMR of the thus treated model compoundrevealed a forest of some 50 peaks of varying sizes, and only a verysmall peak at −98 ppm. ATR showed no detectable peak at 970 cm⁻¹.

Example 5 Resistance to Aqueous Hydrolysis at 325° C.

A specimen of the P1-CN film was treated as in Example 1a except thatthe duration at 70° C. was 48 hours. Following treatment with Cl—F, thethus treated film was heated for 1 hour at 300° C. The resulting film isherein designated P1-CF₂CF₂-P1-5. Four specimens taken from theP1-CF₂CF₂-P1-5 film were added to 180 ml of deionized water in aHastelloy® autoclave The autoclave was heated to 325° C. and held attemperature for 168 hours. After 168 hours, the autoclave was cooled andthe specimens recovered. The thus recovered specimens were a dark,translucent brown, and elastic and strong when stretched by hand. Theweight change for the four specimens is shown in Table 2.

TABLE 2 Film Starting Recovered % Change in Sample Weight (g) Weight (g)Weight #1 0.5456 0.5438 −0.3 #2 0.5129 0.5221 +1.8 #3 0.6533 0.6782 +3.8#4 0.2023 0.2096 +3.6

Example 6 Nitrogen Loss During Crosslinking

A perfluoroelastomer containing copolymerized monomers of TFE, PMVE, and8CNVE was prepared as follows. Three aqueous streams were each fedcontinuously to a 2 liter, mechanically stirred, water jacketed,stainless steel autoclave at a rate of 162 cubic centimeters per hour(cc/hr). The first stream consisted of a solution of 12.8 g ammoniumpersulfate in 5 kg of deionized, deaerated water. The second streamconsisted of 249.5 g of F(CF₂)₅—CH₂O—PO₂(OH)(NH₄) surfactant and 41.6 gof Krytox® 157FSL surfactant in 5 kg of deionized, deaerated water. Thethird stream consisted of a solution of 77.0 g disodium hydrogenphosphate heptahydrate in 5 kg of deionized, deaerated water. Using adiaphragm compressor, a mixture of TFE (145.5 g per hour (g/hr)) andPMVE (82.8 g/hr) was fed at a constant rate. Using a syringe pump,8-CNVE was fed to the reactor at a rate of 5.25 milliliters per hour.The temperature was maintained at 85° C., and the pressure at 4.1 MPa(600 psig) throughout the reaction. The polymer emulsion was removedcontinuously by means of a letdown valve and the unreacted monomers werevented. The emulsion was collected and then diluted by adding 8 litersof deionized water per liter of emulsion. The diluted emulsion wastreated with 1% H₂SO₄ solution until its pH was 3.0. After pHadjustment, the emulsion was coagulated with magnesium sulfateheptahydrate and washed with deionized water. The polymer was then driedat 70° C. for 48 hours. Mooney viscosity, ML-175 (1+10), was 39.6,determined according to ASTM D1646 with an L (large) type rotor at 175°C., using a preheating time of 1 minute and a rotor operation time of 10minutes. The polymer had an inherent viscosity of 0.57. Polymercomposition by NMR: 62.5 wt TFE, 34.0 wt % PMVE, 3.48 wt % 8-CNVCNE[74.5 mole % TFE, 24.4 mole % PMVE, 1.1 mole % 8-CNVE].

The polymer so prepared is herein designated P3-CN.

Nitrogen concentration in the P3-CN was determined with an Antek® NSAnalyser using combustion analysis, and by NMR. The polymer was found tohave 1381 ppm N by the former method, and 1246 ppm N by fluorine NMRusing the —CF₂CN resonance to track 8-CNVE content.

A 30 g sample of the P3-CN polymer in the form of fine crumb was addedto a 400 ml Hastelloy® autoclave. The autoclave was evacuated andpressured with Cl—F (99% pure, Advance Research Chemicals, Catoosa,Okla.) to 24 psig at −10° C. The contents of the autoclave were agitatedas the autoclave was heated to 70° C. over about 45 minutes and thenheld at 70° C. for 16 hours at an internal pressure of 40 to 39 psig.The polymer thereby prepared, herein designated P3-CF₂NCl₂-6, wasrecovered and purged with N₂ to get rid of residual Cl₂ and Cl—F. A 2 gsample of the thus prepared P3-CF₂NCl₂-6 polymer was hot pressed 3min/90° C./0 lb, 3 min/90° C./3000 lb making a roughly 2 in. circularfilm. A strip cut from the thus prepared film was heated for 1 hour at300° C. under a flow of nitrogen.

A Hastelloy® tube (26 in. long, ⅞ in. I.D., 1 in. O.D) was swept with aslow nitrogen flow as its center 14″ was heated using a clamshellLindberg tube furnace set to 300° C. The first polymer film strip wasplaced on the flat end of an 18″ long stainless steel spatula, that waspositioned at roughly the center of the heated area. After 1 hour, thespatula was withdrawn from the heated Hastelloy® tube and the polymerfilm recovered from the spatula tip. The thus prepared film is hereindesignated P3-CF₂CF₂-P3-6. The nitrogen concentration of theP3-CF₂CF₂-P3-6 was found, by the method described supra, to be 251 ppm,an 82% decrease.

Examples 7 and 8 Effect of Pure Cl—F and Effect of Atmosphere onConversion

A 25 g sample of the P3-CN of Example 6 in the form of fine crumb wasadded to a 400 ml Hastelloy® autoclave. The autoclave was evacuated andpressured to −6 psig with Cl—F (99% pure, Advance Research Chemicals,Catoosa, Okla.). The contents of the autoclave were agitated as theautoclave was heated to 70° C. over about 45 minutes and then held at70° C. for 16 hours at an internal pressure of −1 to −2 psig. Thepolymer thereby prepared, herein designated P3-CF₂NCl₂, was recoveredand purged with N₂ to get rid of residual Cl₂ and Cl—F.

A 1 gram sample of the thus prepared P3-CF₂NCl₂ polymer was pressed, asdescribed supra, for 3 min/90° C./0 lb, 3 min/90° C./3000 lbs to get anattractive approximately circular film ˜1.6 in. in diameter by 0.012 in.thick. A 0.094 g strip cut from the thus prepared film was rolled with 2g of PF-5052, as described supra, giving partial viscous solution withnumerous gel particles over a wide range of sizes, and no retention ofthe original film shape.

Two additional strips of film were cut from the pressed P3-CF₂NCl₂ filmprepared above. The first strip (Example 7) weighed 0.0918 g. The firststrip was heated at 300° C. for 1 hour using the method of Example 6,under a nitrogen purge. It was found that after treatment the firststrip weighed 0.0904 g (a 2% weight loss). Rolling the thus heated firststrip with 2 g of PF-5052, as described supra, resulted in a weight gainto 0.2330 g (a 158% weight increase). The strip of film retained itsintegrity and merely swelled.

The second polymer film strip (Example 8) weighed 0.1238 g. The secondstrip was subject to the same 300° C. heating for 1 hour as was thefirst strip except that the nitrogen stream was replaced by an airstream. After treatment, the second strip weighed 0.1219 g (a 2% weightloss). Rolling the thus heated first strip with 2 g of PF-5052, asdescribed supra, resulted in a weight gain to 0.3166 g (a 160% weightincrease). Again the strip of film retained its integrity and merelyswelled.

Examples 9 and 10 Surface Area Effects on Conversion

A 13 g sample of P3-CN crumb was pressed in a mold 0.060 in. thick by1.75 in. square for 10 min/125° C./0 lb, 10 min/125° C./5000 lbs. Whenthis amount of material was found to not quite fill the mold another 3 gof polymer were added and the polymer re-pressed for 10 min/150° C./0lb, 10 min/150° C./5000 lbs.

A five gram sample of the polymer P3-CN in the form of crumb was loadedinto a stainless steel Waring blender along with liquid nitrogen and theblender was run until the polymer crumb was reduced to fine granules.

The thus prepared molded sheet and the thus prepared granules wereloaded into a 400 ml autoclave. The autoclave was evacuated and thenfilled with 14 psi of Cl—F (Advance Research Chemicals) bringingpressure in the autoclave to 5 psig. After 91 hours at 22-33° C., thepressure in the autoclave had decreased to 4 psig, and both the granularpolymer and the molded sheet were recovered and purged with nitrogenaccording to the purge method described supra. The molded sheet thusprepared is herein designated P3-CF₂NCl₂-9. The granular specimen thusprepared is herein designated P3-CF₂NCl₂-10.

ATR spectra were taken of the sheet and granules. The area ratio of the1036 cm⁻¹ band to the 889 cm⁻¹ band of the P3-CN polymer granules was0.7160. P3-CF₂NCl₂-10 granules exhibited a 1036/889 cm⁻¹ peak ratio of0.6206. P3-CF₂NCl₂-9 molded sheet exhibited a 1036/889 cm⁻¹ peak ratioof 0.3144 and 0.3018 for the two sides of the molded sheet. About 14% ofthe —CN groups in the granules and about 57% of the —CN groups at leastat the surface of the thick film were converted to —CF₂NCl₂ groups. The—CF₂NCl₂ groups show up in the ATR at 960 cm⁻¹, the granules having a960/889 cm⁻¹ area ratio of 0.0620 and the two sides of the thick filmshowing 960/889 cm⁻¹ area ratios of 0.1649 and 0.1691.

A 1 gram sample of the P3-CF₂NCl₂-10 granules was pressed 3 min/90° C./0lb, 3 min/90° C./3000 lbs. to get an approximately circular film 1.5 in.in diameter. An ATR spectrum thereof showed the 1036/889 cm⁻¹ and960/889 cm⁻¹ area ratios to be 0.6515 and 0.0614 respectively,essentially unchanged from before pressing. A specimen of theP3-CF₂NCl₂-10 film was heated for 24 hours at 70° C. under N₂ and theATR spectrum taken again this time showing area ratios 1036/889cm⁻¹=0.6148, 960/889 cm⁻¹=0.0880. The 970 cm⁻¹ absorption was notdetected.

A strip of the thus pressed P3-CF₂NCl₂-10 film was heated for 1 hour at300° C. in a nitrogen purge, according to the method of Example 6. AnATR of the thus heated film, herein designated P3-CF₂CF₂—P3-10 showedcomplete loss of the —CF₂NCl₂ group (the 960 cm⁻¹ absorption was notdetected), replaced by the —CF₂CF₂— crosslink (area ratio 970/889cm⁻¹=0.2542). A 0.0860 g strip cut from the P3-CF₂CF₂-P3-10 film wasrolled with 2 g of PF-5052, as described supra. The weight of the thusrolled strip increased to 0.2500 g (191% weight gain)

A 2.4637 g strip of the P3-CF₂NCl₂-9 sheet was heated for 1 hour at 300°C. under N₂ using the method of Example 6. The sheet so prepared, hereindesignated P3-CF₂CF₂-P3-9, weighed 2.4487 g. A 0.4793 g piece of thethus prepared P3-CF₂CF₂-P3-9 sheet was rolled with 2 g of PF-5052, asdescribed supra. The thus rolled P3-CF₂CF₂-P3-9 sheet weighed 2.2264 g(365% weight gain).

Example 11 2.35 wt-% 8-CNVE

Poly(TFE/PMVE/8-CNVE) crumb elastomer that contained 2.35 wt % 8-CNVE,˜49 wt % TFE, ˜49 wt % PMVE was prepared according to the method taughtin U.S. Pat. No. 5,789,489. The polymer so prepared is herein designatedP4-CN. An aliquot of P4-CN was placed into liquid N₂ contained in astainless steel Waring blender, and chopped to finer granules, a mixranging from dust-like fines up to the rare angular particle ˜2-3 mm indiameter. A 400 ml autoclave was loaded with 25 g of the thus granulatedP4-CN polymer, the autoclave was evacuated, and 40 psig of the Cl₂/Cl—Fmixture prepared as in Example 1a was added. The autoclave was heatedfor 16 hours at 70° C. while its contents were shaken. 24.94 g ofpartially fused polymer was recovered, herein designated as P4-CF₂NCl₂.

A 1 gram sample of the thus prepared P4-CF₂NCl₂ polymer was pressed 3min/90° C./0 lb, 3 min/90° C./5000 lbs to produce a slightly hazy filmabout 1.9 in. in diameter.

A 0.0841 g slice of the thus pressed P4-CF₂NCl₂ film was heated for 1hour at 300° C. according to the method of Example 6. The thus treatedfilm, herein designated as P4-CF₂CF₂-P4-11 weighed 0.0833 g. The thusprepared P4-CF₂CF₂-P4-11 film was rolled with 2 g of PF-5052, asdescribed supra. The rolled film weighed 0.2523 g (203% weight gain).

Example 12 Photochemical Conversion of Sheet

A 30 g sample of granulated P3-CN polymer was added to a 400 mlHastelloy® autoclave. The autoclave was evacuated and pressured to ˜24psig at −10° C. with Cl—F (Advance Research Chemicals). The contents ofthe autoclave were agitated as the autoclave was heated to 70° C. overabout 45 minutes and then held at 70° C. for 16 hours at an internalpressure of 40 to 39 psig. The polymer was recovered and purged with N₂to get rid of residual Cl—F. The thus prepared polymer is hereindesignated P3-CF₂NCl₂-12

A 1.0 gram sample of the thus prepared P3-CF₂NCl₂-12 polymer was pressedas described supra, in a hydraulic press: 3 min/120° C./0 lb, 3 min/120°C./3000 lbs thereby preparing a film ranging in thickness from 0.010 to0.013 in. in thickness and approximately 1.6 in. in diameter, hereindesignated P3-CF₂NCl₂-12a.

A 0.0711 g strip of the thus prepared P3-CF₂NCl₂-12a film was heated for1 hour at 300° C. in an N₂ atmosphere according to the method of Example6. The thus heated film, herein designated P3-CF₂CF₂—P3-12a, weighed0.0698 g. When the 0.0698 g strip of thin film was rolled with 2 g ofPF-5052, the weight of the thus rolled strip was 0.1666 g (139% weightgain).

Separately a 12 g sample of the P3-CF₂NCl₂-12 polymer was hot pressed ina 2.5″ square mold 0.060 in. deep using the following procedure: 5min/90° C./0 lb, 5 min/90° C./5000 lbs (incompletely fused), 5 min/90°C./0 lb, 5 min/90° C./5000 lbs (still incompletely fused), and finally10 min/118° C./0 lb and 10 min/118° C./5000 lbs to make a transparentsheet free of unfused particles, herein designated P3-CF₂NCl₂-12b.

It was observed that the temperature required to thoroughly fuse thedichloroamino polymers in a practical time frame, such as within an houror so, increased with the thickness of the specimen. A half inch thickspecimen can require a temperature of around 180° C., which will inducecrosslinking during melting, significantly degrading the quality of themolded piece.

A 0.2715 g piece was cut off the edge of the 0.060 in. thickP3-CF₂NCl₂-12b sheet using scissors. This piece was heated for 1 hour at300° C. under an N₂ atmosphere, according to the method of Example 6.The thus heated piece, herein designated P3-CF₂CF₂—P3-12b weighed 0.2669g. When the thus prepared 0.2669 g piece of P3-CF₂CF₂—P3-12b sheet wasrolled, as described supra, with 2 g of PF-5052, its weight increased to0.6703 g (151% weight gain).

A 1 kilowatt Mercury Short Arc Lamp (Advanced Radiation Corporation) wasused to irradiate portions of both the P3-CF₂NCl₂-12a thin film and theP3-CF₂NCl₂-12b sheet. This lamp delivered a power intensity of 6milliwatt/cm² at 365 nm, 10 milliwatt/cm² at 405 nm, and 6.7milliwatt/cm² at 436 nm. Irradiation was carried out on each specimenfor 8 hours in a nitrogen atmosphere in a clean room. The resultingspecimens are herein designated P3-CF₂N═NCF₂—P3-12a andP3-CF₂N═NCF₂—P3-12b.

A 0.1025 g strip cut from the thus prepared P3-CF₂N═NCF₂—P3-12a film wasrolled with 2 g of PF-5052, as described supra. The thus rolled filmweighed 0.1784 g (74% weight gain). A 0.3958 g piece cut from the thusprepared P3-CF₂N═NCF₂—P3-12b sheet was rolled with 2 g of PF-5052, asdescribed supra. The thus rolled sheet weighed 0.7960 g (101% weightgain). The low weight gain in the solvents, and retention of specimenintegrity are clear indicators of crosslinking having taken place.

ATR spectra were consistent with crosslinking having occurred to the azocrosslinked material represented by Structure III, but not havingprogressed further to the perfluoroalkyl-crosslinked materialrepresented by Structure IV, namely, no 970 cm⁻¹ band was detected.Further, when a specimen of the irradiated 0.060 in. sheet was subjectto heating for 1 hour at 300° C. under N₂, according to the method ofExample 6, ATR on the thus heated specimen showed that the—CF2CF2-crosslink band at 970 cm⁻¹ had appeared with a 970/889 cm⁻¹ arearatio of 0.1346. The specimen still showed a small weight gain (117%)and maintenance of integrity upon solvent exposure.

After the UV exposure step, ATR spectra taken on both the top and bottomsides of the P3-CF₂N═NCF₂—P3-12b sheet showed virtually no remaining—NCl2 groups (peak area ratios at 960/880 cm⁻¹=0.0000 and 0.0025 for topand bottom respectively) consistent with essentially complete UVconversion of polymer-NCl2 to polymer-azo-polymer through the fullthickness of the specimen.

Example 13 Conversion in Solution

A gelatinous solution was made by rolling 10 g of polymer P1-CN with 90g of PF-5052, as described supra. The resulting gelatinous solution wascharged to a 400 ml autoclave. The autoclave was chilled, evacuated, and70 psig of the Cl—F/Cl₂ mix as prepared in Example 1a, was added at −42°C. The chilling was done to keep the vacuum pump from either pulling thelow boiling PF-5052 out of the autoclave or sucking foamed polymersolution down the lines into the pump. The autoclave was shaken for 2hours at room temperature and then for 2 hours at 70° C. The resultingproduct was a yellow gel with the consistency of cottage cheese thatevaporated down under a nitrogen purge to 9.62 g of white polymerP1-CF₂NCl₂-13. A 0.035 g aliquot of the thus prepared of P1-CF₂NCl₂-13was rolled with 2.6 g of PF-5052. The sample broke up into swollen gelparticles as had the starting P1-CN.

A 0.0932 g piece of P1-CF₂NCl₂-13 was heated for 1 hour using the methodof Example 6 except that the temperature was 200° C. instead of 300° C.,to prepare a mixture of polymers herein designatedP3-CF₂NCl₂/P3-CF₂N═NCF₂—P3-13. The P3-CF₂NCl₂/P3-CF₂N═NCF₂—P3-13 wasrolled with 2.8 g of PF-5052. The thus treated polymer weighed 0.6435 gfor a 590% weight gain.

An aliquot of P1-CF₂NCl₂-13 polymer was mounted in a moving dierheometer (MDR) set at 200° C. The initial torque was just under 1 dNm.After 240 minutes the torque was observed to have increasedmonotonically to above 8 dNm, and was still increasing, indicating thatcrosslinking was still not yet complete.

Example 14 Treatment of Hard Plastic

An 400 ml autoclave was chilled to below −20° C. The thus chilledautoclave was then charged with 6.5 ml of 8-CNVE dissolved in 50 ml ofVertrel® XF hydrofluorocarbon fluid from DuPont, 10 ml of Vertrel® XF inwhich HFPO dimer peroxide was at a concentration of 0.17 M, and 24 g ofperfluoro-2,2-dimethyl-1,3-dioxole(PDD). The chilled autoclave wasevacuated, and further charged with 9 g of TFE and then sealed.

The thus charged autoclave was shaken at room temperature. The pressurein the autoclave reached a maximum of 24 psig at 18.6° C. at 32 minutesinto the run and then decreased to −5 psig at 25.5° C., 1068 minuteslater. The reaction product was a polymer wet and swollen with fluid.The reaction product was mixed with 100 ml of acetone and vacuumfiltered. The solids residue was rinsed in the filter with an additional325 ml of acetone. The residue was then sucked dry in the filter,followed by drying overnight in a 50° C. vacuum oven. The yield was 32 gof polymer. Differential Scanning calorimetry (DSC: 10° C./min, N₂,2^(nd) heat) revealed a T_(g) at 100° C. and another at 207° C. FluorineNMR found 52.1 mole % TFE, 43.1 mole % PDD, and 4.78 mole % 8-CNVEmonomer. Inherent viscosity in perfluoro-N-methylmorpholine at 25° C.was 0.718 dL/g. The polymer thus prepared is herein designated P5-CN-14.

Cl—F Treatment of P5-CN-14.

The P5-CN-14 polymer thus prepared was combined with liquid nitrogen ina stainless steel Waring blender cup, and ground to form granulesranging in size from dust like fines to irregular particles several mmacross. A 25.0 g aliquot of the thus granulated granular P5-CN-14 wasloaded into a 400 ml autoclave, the autoclave evacuated, and 40 psig ofthe Cl₂/Cl—F prepared as in Example 1a was added at room temperature.The contents of the autoclave were then heated and shaken for 16 hoursat 70° C. during which negligible change in pressure was observed. The24.7 g of P5-CF₂NCl₂-14 granules recovered from the autoclave werepurged with N₂ according to the method described supra.

A 0.2 g aliquot of the thus prepared P5-CF₂NCl₂-14 was rolled with 2 gof PF-5052 as described supra, resulting in a clear, colorless solution.The droplets of the solution were applied to a glass surface using amedicine dropper, forming a film. The film so formed was allowed to airdry sitting in the draft of a fume hood, thereby forming a thin film ofP5-CF₂NCl₂-14.

A 0.0180 g piece cut from the P5-CF₂NCl₂-14 film was exposed toirradiation for 71 hours under nitrogen with the UV light from a single2537A Rayonet bulb (approximate intensity at film 0.17 mWatt/cm²), asdescribed supra. The thus irradiated film sample, herein designatedP5-CF₂N═NCF₂—P5 was then rolled with 2 g of PF-5052, as described supra.The P5-CF₂N═NCF₂—P5 specimen retained its integrity, and increased inweight to 0.0293 g (63% weight gain) rather than dissolving.

A 1 g sample of the granular P5-CF₂NCl₂-14 was hot pressed 3 min/190°C./0 lb, 3 min/190° C./5000 lbs to make a stiff, approximately circularfilm 2.1 in. in diameter, referred to herein as the polymer mixtureP5-CF₂NCl₂-14/P5-CF₂N═NCF₂—P5. Rolling a 0.0511 g strip of theP5-CF₂NCl₂-14/P5-CF₂N═NCF₂—P5 film with 2 g of PF-5052 resulted in agelatinous solution. The term “gelatinous solution” refers to a hazysolution wherein there is evidence of gel (by visual observation: lotsof particles, some floating, some stuck to the walls, some particlesvery small). The liquid phase noticeably increased in viscosity.

An additional 0.0825 g strip of the P5-CF₂NCl₂-14/P5-CF₂N═NCF₂—P5 filmwas heated for 1 hour at 300° C. under N₂ according to the method ofExample 6, causing it to decrease in weight to 0.0803 g, forming a filmherein designated P5-CF₂CF₂—P5. Rolling the P5-CF₂CF₂—P5 film with 2 gof PF-5052 caused it to increase in weight to 0.1740 g (117% weightincrease).

A fresh 1 g aliquot of the P5-CF₂NCl₂-14 polymer was pressed asdescribed supra, 3 min/200° C./0 lbs, 3 min/200° C./5000 lbs to give aninhomogeneous looking film that was cut into pieces and pressed a secondtime for 3 min/220° C./0 lbs, 3 min/220° C./5000 lbs. In this secondpressing the polymer was so crosslinked that the pieces failed to fusetogether at all.

Example 15 Hydrofluorocarbon Polymer

24 liters of deoxygenated, deionized water was charged to a 33-literstainless steel reactor equipped with an agitator. Oxygen was displacedfrom the reactor by a nitrogen sweep, and then the reactor waspressurized to 1.38 MPa with a mixture of 59 mol-% VF₂ and 41 mol-% HFP.400 mL of a 10% ammonium persulfate/10% diammonium phosphate initiatorsolution was charged to the reactor. The reactor pressure declined dueto polymerization and a mixture of 78 mol-% VF₂ and 22 mol-% HFP was fedto the reactor to maintain a 1.38 MPa pressure. After 50.0 g of thisVF2+HFP monomer mixture had been fed, an 8-CNVE feed was commenced at arate of 41.5 mL per 3000 g of VF₂+HFP monomer mixture. The 8-CNVE feedcontinued until 5500 g VF₂+HFP monomer mixture had been fed, for a totalof 75.5 mL 8-CNVE. After 6000 g of VF₂+HFP monomer mixture had been fed,the reaction was halted by depressurization of the reactor to obtain a20.15% solids dispersion with a pH of 4.1. The dispersion was coagulatedwith magnesium sulfate to give a polymer with a Mooney viscosity, ML-121(1+10), of 65.6, determined according to ASTM D1646 with a L (large)type rotor at 121° C., using a preheating time of 1 minutes and a rotoroperation time of 10 minutes. T_(g) was determined by DSC to be −18.9°C.

The polymer was estimated by IR to be 76.7 mole % VF₂, 22.9 mole % HFP,and 0.4 mole % 8-CNVE (on basis of amount of monomer added toautoclave). The polymer so produced is herein designated P6-CN.

A 1 gram sample of the thus prepared P6-CN was hot pressed for 3 min/90°C./0 lb, 3 min/90° C./5000 lbs to form an approximately circular film1.6 inches in diameter

A 0.078 g strip was cut from the thus formed P6-CN film, and was rolledwith 2 g of methyl ethyl ketone (MEK) causing the film to break up intoa multitude of swollen gel particles.

A 50 g aliquot of the P6-CN polymer was mixed with liquid N₂ andgranulated in a stainless steel Waring blender. A 400 ml autoclave at22° C. was charged with 50 g of the thus formed granules, and then wasevacuated. A room temperature Cl₂/Cl—F mixture prepared as in Example 1was then charged to the autoclave to a pressure of 40 psig. Theautoclave was shaken for 16 hours at 70° C., the pressure in theautoclave was observed to have dropped from 46 psig observed when theautoclave was initially heated to 70° C. to 42 psig after 16 hours at70° C. 48.7 g of thus treated granules were recovered, and hereindesignated P6-CF₂NCl₂. Some of the granules were observed to have formedagglomerates

A 1.0 g aliquot of the thus prepared P6-CF₂NCl₂ granules were hotpressed for 3 min/90° C./0 lbs, 3 min/90° C./5000 lb resulting in anapproximately circular film. A 0.1201 g strip was cut from theP6-CF₂NCl₂ film, and heated for 1 hour at 300° C. in a N₂ atmosphereaccording to the method of Example 6. The resulting film is designatedherein as P6-CF₂CF₂—P6. The thus prepared P6-CF₂CF₂—P6 film weighed0.1194 g. Rolling the P6-CF₂CF₂—P6 film with 2 g of MEK caused the filmto increase in weight to 0.4787 g (302% weight gain).

Example 16 Imageable Article

A 1.0 gram aliquot of the P5-CF₂NCl₂-14 polymer was dissolved in 18 g ofPF-5052, and the resulting solution was filtered using a 0.45 micrometerglass syringe filter. A solution made by diluting 1 ml of this filtratewith 1 ml of Fluorinert FC-40 was spin coated on a clean silicon waferat 500 rpm for 1 minute. The thus coated silicon wafer was then placedon a 65° C. hot plate until the color of the film stabilized(approximately 30 seconds) as solvent evaporation was completed.

Film Exposure:

A chrome photomask presenting multiple test patterns was pressed lightlyon top of the film on the silicon wafer. Mask and wafer were then placedin a N₂-purged exposure box and exposed for 730 seconds using a 350 watthigh-pressure short-arc lamp with an output of 12 milliwatts/cm² (OAIModel 200 mask aligner and UV exposure tool that emits UV-A radiationaround 360-400 nm). The N₂-purged exposure box was next placed under an8 watt Entela UV lamp for an additional two hours; lamp output was 1.4mW/cm² at 365 nm.

Pattern Development:

After separating from the photomask, the wafer was agitated for 1-2minutes in Fluorinert FC-40 solvent in order to remove uncrosslinked,still-soluble polymer. This left UV crosslinked polymer behind on thesilicon wafer in the form of raised lines. FIG. 1 is an opticalmicrograph, taken from above the sample disk. The lines were ca. 20micrometers and 50 micrometers wide respectively. FIG. 2a shows anAtomic Force Microscopy (AFM) image of the sample in a region havingfiner lines than in FIG. 1. FIG. 2b shows a so-called sectional analysisof the surface shown in FIG. 2a . Examination of FIGS. 2a and 2b revealsthat the raised surface features are about 15 micrometers wide, 800nanometers high, and 20-25 micrometers apart from one another.

Example 18 Azo to —CF₂CF₂— Conversion Under Cl₂

A. A 5 g film sample P3-CN was placed on a Teflon® FEP film and the twotogether were positioned into a 400 ml autoclave. The autoclave wasevacuated, and then pressured to 40 psig with Cl—F as prepared inExample 1a. The autoclave was heated for 7 hours at 70° C. and 24 hoursat 150° C., conditions that created primarily a film designated hereinas P3-CF₂N═NCF₂—P3-18a with some residual P3-CF₂NCl₂. The thus treatedfilm was recovered and purged with N₂ to get rid of residual Cl—F andCl₂. A 0.1929 g strip was cut from the P3-CF₂N═NCF₂—P3-18a film, and washeated for 1 hour at 300° C. under a N₂ flow according to the method ofExample 6, to produce a strip of film herein designatedP3-CF₂CF₂—P3-2-18a. The P3-CF₂CF₂—P3-18a strip was rolled with PF-5052,as described supra. The weight of the thus rolled strip was 0.4632 g(140% weight gain).

B. Completion of Crosslinking at 300° C. Under Cl₂ Gas.

The procedures of Example 18 part A were repeated with a fresh 5 g filmsample of P3-CN to produce a new film sample of P3-CF₂N═NCF₂—P3-18b withresidual P3-CF₂NCl₂. However, instead of recovering the thus preparedfilm at this point, the autoclave was evacuated and pressured to 10 psigwith Cl₂. The autoclave was then heated for 1 hour at 300° C.,generating an internal Cl₂ pressure of 33 psig. The film strip thusprepared is herein designated P3-CF₂CF₂—P3-2-18b. A 0.3915 g strip wascut from the P3-CF₂CF₂—P3-2-18b film, and was rolled with 2 g ofPF-5052, as described supra. The thus rolled film weighed 0.3915 g (137%weight gain).

Example 19 Crosslink Stability Under F₂

A 15.2 g sample of polymer P3-CN crumb was pressed in a mold for 10min/125° C./0 lb, 10 min/125° C./5000 lbs to make a sheet 1.75 in.square by 0.160 in. thick. The sheet so prepared was yellow with faintbrown speckling. The sheet so prepared was placed flat on a Hastelloy®sheet, and, together, they were placed into a 400 ml autoclave. Theautoclave was evacuated. Pressure in the clave brought from −14 to 0psig with Cl—F (Advance Research Chemicals). The autoclave was heated inthe following series of steps: 1 hr at 75° C., 1 hr at 100° C., 1 hr at125° C., 1 hr at 150° C., 1 hr at 175° C., and 6 hrs at 200° C. Theautoclave was cooled back to room temperature, purged of Cl—F, openedand 10 ml of PF-5052 added avoiding physical contact of the liquidPF-5052 with the polymer. The clave was evacuated and pressure in theclave brought from −11 to 4 psig with Cl—F. The clave was heated in thefollowing series of steps: 4 hrs at 75° C., 4 hrs at 100° C., 4 hrs at125° C., 4 hrs at 150° C., 4 hr at 175° C., and 30 hrs at 200° C. Thesheet so prepared is herein designated P3-CF₂N═NCF₂—P3/P3-CF₂CF₂—P3-19.Upon recovery, the film weighed 20.1 g, the weight increase being causedby the absorption of PF-5052. Absorbed PF-5052 was removed by heatingfor 68 hours in a 100° C. vacuum oven with a N₂ bleed. At this point thefilm was a pale uniform yellow with no sign of the brown speckling.

A 0.1710 gram piece was cut off the edge of the film and rolled with 2 gPF-5052 causing its weight to increase to 0.3906 g (128% weight gain).The 970/889 cm⁻¹ area ratio in the ATR characteristic of the —CF₂CF₂—crosslinks was 0.24.

Reaction with F₂:

A square corner weighing 3.3764 g was cut off from theP3-CF₂N═NCF₂—P3/P3-CF₂CF₂—P3-19 film, and was placed flat on aHastelloy® sheet that was then inserted into a 400 ml Hastelloy®autoclave. The autoclave was then evacuated. Pressure within theautoclave was raised from −13 to 6 psig with a gaseous mixture of 25mol-% F₂ in nitrogen. The autoclave was heated for roughly 1 hr at 75°C., 1 hr at 100° C., 1 hr at 125° C., 1 hr at 150° C., 1 hr at 175° C.,and 6 hrs at 200° C. The recovered film weighed 3.3119 g and wasbleached colorless. A 0.2274 g piece cut off the edge of the film wasrolled with 2 g PF-5052 increasing its weight to 0.6680 g (194% weightgain). ATR found a 970/889 cm-1 area ratio of 0.24, exactly the same asbefore fluorine treatment.

Example 20 Thickness Effect

A. Five 13 gram samples of P3-CN crumb were pressed in a mold for 10min/120° C./0 lb, 10 min/120*C/5000 lbs to make five sheets, each 2.5inches square by 0.060 in. thick. Disks 15 mm in diameter by 0.060 in.thick were cut out using a die. A pellet mold was made in the cavity ofa press by stacking in succession a steel plate, a Kapton® film, a 0.5″thick steel plate having a 0.75 in. diameter circular hole withadjoining overfill cavities, a second Kapton film, and a third steelplate. The mold was preheated to 180° C. in a heated hydraulic press.Seven to eight grams of the circular P3-CN disks were loaded into thepreheated mold cavity. The upper Kapton® film and steel plate were setin place and the platens of the press closed only to contact pressure.The thus filled mold equilibrated for 5 minutes under contact pressure,and then 30,000 lbs of ram force was applied for 2 minutes. The mold wasremoved from the press, and the pellet thus formed was removed once themold had cooled back to ambient. Molded pellets typically measured about0.75 inch high by 0.5 inch wide and weighed about 6.75 g.

Seven such pellets were prepared. The pellets so prepared were slightlyyellow in color, had occasional black spots, and occasional bubbles. Thepellets so prepared are herein designated P3-CN-20a

B. Two P3-CN-20 pellets were loaded into a 400 ml autoclave, theautoclave was evacuated, and then filled with 2 g of Cl—F (AdvanceResearch Chemicals). The autoclave was then heated in the followingseries of steps: 7 hours at 75° C., 2 hours at 100° C., 2 hours at 125°C., 2 hours at 150° C., 2 hours at 175° C., 2 hours at 200° C., 2 hoursat 250° C., and 2 hours at 300° C. with pressure in the autoclaveobserved to increase from at 12 psig at 22.1° C. to 37 psig at 300.6° C.The autoclave was cooled to room temperature, the pellets recovered andpurged with nitrogen for 70 hours. The pellets so treated, hereindesignated P3-CF₂CF₂—P3-20b, appeared to be unchanged in shape exceptfor some internal bubble formation. One of the pellets, a pellet with afew bubbles between two of the layers that had been pressed together tomake the pellet, was cut longitudinally through its center traversingthe 0.5″ distance from top to bottom. ATR was then used to measure theintensities of the 970 cm⁻¹ and 889 cm⁻¹ absorption bands approximatelyevery mm from the top to the bottom of the cut with the results shown inTable 3. Significant —CF₂CF₂ crosslink formation as measured by ATRabsorption at 970 cm⁻¹ was observed only to a depth of 2-3 mm along thecross sectional cut.

TABLE 3 Peak Area Ratio Distance from 970 cm⁻¹/889 cm⁻¹ Top (mm) Example20 Example 21 0 0.1442 0.4050 1 0.0298 0.5436 2 0.0394 0.8253 3 0.04290.7551 4 0.0553 0.8487 5 0.0588 1.0176 6 0.0509 0.9157 7 0.0545 0.8655 80.3811 0.7156 9 0.4616 0.6862 10 0.5029 0.4032

Nitrogen analysis of a specimen cut from the surface of aP3-CF₂CF₂—P3-20b pellet found 56 ppm N in P3-CF₂CF₂—P3-19a vs. 1381 ppmN in P3-CN starting polymer.

Example 21 Solvent Assisted Diffusion of Reactants

A. One of the P3-CN-20a pellets was loaded into a 400 ml autoclave, theautoclave was evacuated, and then filled with 2 g of Cl—F (AdvanceResearch Chemicals). The autoclave was then heated in the followingseries of steps: 1 hour at 75° C., 1 hour at 100° C., 1 hour at 125° C.,1 hour at 150° C., 1 hour at 175° C., and 6 hours at 200° C. Theautoclave was vented, purged with nitrogen, evacuated, and then 10 ml ofPF-5052 was injected followed by addition of 2 g of Cl—F (AdvanceResearch Chemicals). The autoclave was again heated, in the followingseries of steps: 1 hour at 75° C., 1 hour at 100° C., 1 hour at 125° C.,1 hour at 150° C., 1 hour at 175° C., 1 hour at 200° C., 2 hours at 250°C., and 2 hours at 300° C. Pressure in the autoclave was observed toincrease to 105 psig at 300.8° C. The pellet so treated, hereindesignated P3-CF₂CF₂—P3-21 b, was observed to have been bleachedcolorless throughout. After purging with nitrogen in the mannerdescribed supra to get rid of absorbed solvent and residual Cl—F, thepellet was sliced longitudinally through its center traversing the 0.5inch distance from top to bottom. ATR was then used to measure therelative intensities of the 970 cm⁻¹ band, and the 889 cm⁻¹ bandsapproximately every mm from the top to the bottom of the cut. The datais shown in Table 3.

A further 0.0972 g chunk, designated P3-CF₂CF₂—P3-21c, was cut from theP3-CF2CF2-P3-21b pellet, carving the chunk out of the extreme center ofthe cross-sectioned face. Rolling P3-CF₂CF₂—P3-21c with 2 g of PF-5052caused it to increase in weight to 0.4269 g (339% weight gain). A 0.2393g piece of skin, designated P3—CF₂CF₂—P3-21 d, was cut off the outer,cylindrical wall of the pellet P3-CF₂CF₂—P3-21 b. Rolling P3-CF₂CF₂-20dwith 2 g of PF-5052 caused it to increase in weight to 0.9289 g (288%weight gain).

Example 22 Secondary —CN Group

CF₂=CFO(CF₂)₃OCF(CF₃)CN, herein designated “i-8CNVE,” was preparedaccording to the method described in European Patent Application 710645,08 May 1996.

Three aqueous streams were each fed continuously to a 1 litermechanically stirred, water jacketed, stainless steel autoclave at arate of 81 cc/hr. The first stream consisted of 1.34 g ammoniumpersulfate, 26.2 g of disodium hydrogen phosphate heptahydrate, and 30 gammonium perfluorooctanoate per liter of de-ionized water. The secondstream consisted of 30 g of ammonium perfluorooctanoate per liter ofde-ionized water. The third stream consisted of 1.34 g of ammoniumpersulfate and 30 g ammonium perfluorooctanoate per liter of de-ionizedwater. Using a diaphragm compressor, a mixture of TFE (58.5 g/hr) andPMVE (68.8 g/hr) was fed at constant rate. The liquid i-8CNVE was fed asa separate stream at a rate of 3.5 g/hr. The reaction temperature wasmaintained at 85° C., the pressure at 4.1 MPa (600 psi), and the pH at4.2 throughout the reaction. The polymer emulsion was removedcontinuously by means of a letdown valve and the unreacted monomers werevented. The polymer was isolated from the emulsion by first diluting itwith deionized water at the rate of 8 liter deionized water per liter ofemulsion, followed by addition of 320 cc of a magnesium sulfate solution(100 g magnesium sulfate heptahydrate per liter of deionized water) perliter of emulsion at a temperature of 60° C. The resulting slurry wasfiltered, and the polymer solids obtained from a liter of emulsion werere-dispersed in 8 liters of deionized water at 60° C. After filtering,the wet crumb was dried in a forced air oven for 48 hr at 70° C. Polymeryield was about 124 g per hour of reactor operation. The polymercomposition, analyzed using FTIR, was 56.8 wt % (45.1 mole %) PMVE, 2.09wt % (0.71 mole %) i-8CNVE, the remainder being tetrafluoroethylene. Aparallel analysis by NMR found 51.4 wt % PMVE, 46.7 wt % TFE, and 1.938wt % i-8CNVE [39.6 mole % PMVE, 59.7 mole % TFE, and 0.637 mole %i-8CNVE)]. The polymer had an inherent viscosity of 0.55 measured in asolution of 0.1 g polymer in 100 g of solvent consisting of a 60/40/3volume ratio of hepta-fluoro-2,2,3-trichlorobutane,perfluoro(butyltetrahydrofuran) and ethylene glycol dimethyl ether.Mooney viscosity, ML (1+10), was 35.2, as determined according to ASTMD1646 with an L (large) type rotor at 175° C., using a preheating timeof one minute and rotor operation time of 10 minutes. The polymer thusprepared is herein designated P7-CN

A 2.17 g aliquot of P7-CN, was pressed 3 min/90° C./0 lbs, 3 min/90°C./4000 lbs to get an approximately 2.1 in diameter circle 0.016-0.021in. thick. A 0.1436 g strip cut from the P7-CN film gave a clearsolution when rolled for 2 hours with PF-5052.

A 0.54 g strip cut from the P7-CN film was placed flat on a Hastelloy®sheet, and together they were positioned in a 400 ml Hastelloy®autoclave, the autoclave evacuated, and then pressured from −13 to 2psig with Cl—F (Advance Research Chemicals). The autoclave was heatedfor approximately 10 hours at 70° C. The recovered film, hereindesignated P7-CF₂NCl₂ weighed 0.54 g. A 0.1905 g strip cut from theP7-CF₂NCl₂ film was heated for 1 hour at 300° C. under nitrogen, therebypreparing a film strip herein designated P7-CF₂CF₂—P7-22. The weight ofthe P7-CF₂CF₂—P7-22 strip was 0.1918 g. The P7-CF₂CF₂—P7-22 strip wasrolled with 2 g PF-5052 for 24 hours, the strip still retained itsshape; the weight after rolling was 1.1556 g (502% weight gain).

Example 23 Blend where Monomer Units Differ

A. A 0.5 g aliquot of P4-CF₂NCl₂ granules was placed atop a 0.5 g pieceof P2-CF₂NCl₂ film. The sample so prepared was pressed in theconfiguration described supra under “Sample Preparation at 3 min/50°C./0 lb, 3 min/50° C./3500 lbs.” The resulting film was cut up andre-pressed at 3 min/50° C./0 lb, 3 min/50° C./5000 lbs. The resultingfilm was again cut up and re-pressed at 3 min/50° C./0 lb, 3 min/50°C./5000 lbs at which point the film appeared homogeneous to the nakedeye. The final resulting film, herein designatedP2-CF₂NCl₂/P4-CF₂NCl₂-23 was approximately circular with a diameter ofapproximately 2 in.

B. A 0.0743 g strip cut from the P2-CF₂NCl₂/P4-CF₂NCl₂-23 film washeated for 1 hour at 300° C. under a nitrogen flow using the method ofExample 6. The strip of film so processed, herein designatedP2-CF₂CF₂—P4-23 weighed 0.0685 g. When rolled with 2 g of PF-5052, thestrip of film increased in weight to 0.1153 g, a 68% weight gain. Whiledesignated P2-CF2CF2-P4-23 to highlight the bonding that occurredbetween the two blended components, the film should also containP2-CF₂CF₂—P2 as well as P4-CF₂CF₂—P4 crosslinked species as well.

Example 24 Blend where Monomer Units are the Same

A 0.5 g sample of P4-NCl₂ was mixed with a 0.5 g sample of P5-NCl₂. Thismixture was pressed, as described for the mixture in Example 23, at 3min/90° C./0 lbs and 3 min/90° C./10,000 lbs. The pressing sequence wasrepeated twice, each time the resulting film being cut up betweenpressings. In the third pressing a circular film 2″ in diameter wasprepared, herein designated P4-CF₂NCl₂/P5-CF₂NCl₂-24. A 0.0680 g stripcut from the P4-CF₂NCl₂/P5-CF₂NCl₂-24 film was heated for 1 hour at 300°C. under N₂. The weight of the resulting film, herein designatedP4-CF₂CF₂—P5-24, was 0.0670 g. Rolling the P4-CF₂CF₂—P5-24 strip with 2g of PF-5052 resulted in a strip weighing 0.1700 g, a weight gain of154%. It is expected that the P4-CF₂CF₂—P5 film was intermixed withP4-CF₂CF₂—P4 and P5-CF₂CF₂—P5 moieties.

Example 25 Stabilization Effect

A sample of P3-CN was hot pressed for 15 minutes in a 180° C. mold tomake a yellowed o-ring with brownish flecks, herein designatedP3-CN-25a. The P3-CN-25a o-ring so prepared had a 1.25 in. outerdiameter (O.D.), a 0.139 in. thickness, and weighed 1.8422 g. TheP3-CN-25a o-ring was placed in a 400 ml Hastelloy® autoclave, and theautoclave was evacuated. Pressure in the autoclave was increased from−14 to −5 psig by the addition of 0.5 g of Cl—F (Advance ResearchChemicals). The autoclave was held for 2 hrs at room temperature, thenheated as follows: 2 hrs at 75° C., 2 hrs at 125° C., 2 hrs at 150° C.,2 hrs at 175° C., and 16 hrs at 200° C., followed by cooling to roomtemperature. The o-ring was recovered and then heated for 1 hour at 300°C. in an air oven to complete conversion to P3-CF₂CF₂—P3-25a, which waslargely clear and colorless.

The P3-CF₂CF₂—P3-25a o-ring was placed into a 400 ml Hastelloy®autoclave with 180 ml of water, and the autoclave was evacuated. Theautoclave was then heated to 325° C. and held for 1 week at 325° C.followed by cooling to room temperature. The recovered o-ring was about1.7 in. O.D., and was flattened like a ribbon. In appearance, it wasnoticeably brown and foamed. The o-ring weighed 2.1162 g (a 15% weightgain).

A second o-ring of P3-CN, herein designated P3-CN-25b, was prepared inan identical manner to that of P3-CN-25a, and exhibited identicalinitial dimensions. The P3-CN-25b o-ring weighed 1.8656 g. The P3-CN-25bo-ring was added to a 400 ml Hastelloy® autoclave, and the autoclave wasevacuated. The pressure in the autoclave was increased from −11 to 1 psiby the addition of Cl—F (Advance Research Chemicals). The autoclave washeld for 2 hrs at r.t., then heated as follows: 2 hrs at 75° C., 2 hrsat 125° C., 2 hrs at 150° C., 2 hrs at 175° C., 4 hrs at 200° C., and 4hours at 250° C. The recovered o-ring, herein designatedP3-CF₂CF₂—P3-25b, was clear and colorless.

P3-CF₂CF₂—P3-25b was treated in water in a manner identical to that ofP3-CF₂CF₂—P3-25a. The recovered o-ring came back unchanged indimensions, black, and with its surface noticeably roughened. It weighed1.9277 g (3% weight gain). The o-ring was still flexible and elastic.

What is claimed is:
 1. A perfluoroalkyl-crosslinked polymer representedby Structure IV

wherein each of Π_(α) and Π_(β) is a polymeric radical backbone chaincomprising fluoroalkylene repeat units optionally substituted by etheroxygen, and perfluoroalkyl-crosslinked repeat units at a molarconcentration in the range of a molar concentration of 0.5 to 50 mol-%;where x₁ and x₂ each independently is an integer in the range of 0 to 3;y₁ and y₂ each independently is an integer in the range of 0 to 6, andz₁ and z₂ each independently is an integer in the range of 0 to 3;R₁=(CF₂)_(a)CFR₂, where a is an integer in the range of 0 to 6, and R₂is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;R₁′=(CF₂)_(a)′CFR₂′ where a′ is an integer in the range of 0 to 6, andR₂′ is F or C₁₋₆ perfluoroalkyl optionally substituted by ether oxygen;and, R₃ and R₃′ are each independently F or C₁₋₆ perfluoroalkyloptionally substituted by ether oxygen; with the proviso that y₁ and z₁cannot both be zero; with the further proviso that y₂ and z₂ cannot bothbe zero; with the further proviso that no monomer from which the repeatunit in the backbone chain of said Ha and H polymeric radicals isderived has more than two vinyl hydrogens attached thereto; and, withthe further proviso that Π_(α) and Π_(β) can comprise the same ordifferent repeat units.
 2. The perfluoroalkyl-crosslinked polymer ofclaim 1 wherein Π_(α) and Π_(β) comprise the same repeat units.
 3. Theperfluoroalkyl-crosslinked polymer of claim 1 wherein Π_(α) and Π_(β)comprise different repeat units.
 4. The perfluoroalkyl-crosslinkedpolymer of claim 2 wherein x₁ and x₂=1, y₁ and y₂=1, z₁ and z₂=1, anda=1; R₂=CF₃; and R₃=F.
 5. The perfluoroalkyl-crosslinked polymer ofclaim 1 wherein the molar concentration of perfluoroalkyl-crosslinkedrepeat units is in the range of 0.5 to 50 mol-%.
 6. Theperfluoroalkyl-crosslinked polymer of claim 1 wherein the fluoroalkylenerepeat units comprise a combination of HFP and VF₂ repeat units.
 7. Theperfluoroalkyl-crosslinked polymer of claim 1 wherein the fluoroalkylenerepeat units comprise a combination of TFE and PDD repeat units.
 8. Theperfluoroalkyl-crosslinked polymer of claim 1 wherein at least one of Haand H further comprises perfluoroalkyl vinyl ether repeat units.
 9. Theperfluoroalkyl-crosslinked polymer of claim 1 in the form of a filmdisposed upon a substrate.
 10. The perfluoroalkyl-crosslinked polymer ofclaim 9 in the form of a film disposed upon a substrate.
 11. Theperfluoroalkyl-crosslinked polymer of claim 1 in the form of a shapedarticle.
 12. The perfluoroalkyl-crosslinked polymer of claim 9 in theform of a shaped article.